7Baggers

Chegg, Inc
(NYSE:CHGG) 

CHGG stock logo

Chegg, Inc. operates direct-to-student learning platform that supports students on their journey from high school to college and into their career with tools designed to help them to learn their course materials, succeed in their classes, and save money on required materials. The company offers Cheg...

Founded: 2005
Full Time Employees: 1,401
Founder: Aayush Phumbhra 
CEO: Dan Rosensweig  
Sector: Consumer Defensive
Industry: Education & Training Services

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Quarterly
Annual
    Unit: USD2026-03-31 2025-12-31 2025-09-30 2025-06-30 2025-03-31 2024-12-31 2024-09-30 2024-06-30 2024-03-31 2023-12-31 2023-09-30 2023-06-30 2023-03-31 2022-12-31 2022-09-30 2022-06-30 2022-03-31 2021-12-31 2021-09-30 2021-06-30 2021-03-31 2020-12-31 2020-09-30 2020-06-30 2020-03-31 2019-12-31 2019-09-30 2019-06-30 2019-03-31 2018-12-31 2018-09-30 2018-06-30 2018-03-31 2017-12-31 2017-09-30 2017-06-30 2017-03-31 2016-12-31 2016-09-30 2016-06-30 2016-03-31 2015-12-31 2015-09-30 2015-06-30 2015-03-31 2014-12-31 2014-09-30 2014-06-30 2014-03-31 2013-12-31 
                                                      
      net revenues
    63,262,000 72,659,000 77,742,000 105,120,000 121,387,000 143,484,000 136,593,000 163,147,000 174,350,000 187,987,000 157,854,000 182,853,000 187,601,000 205,193,000 164,739,000 194,721,000 202,244,000 207,467,000 171,942,000 198,478,000 198,378,000 205,721,000 154,018,000 153,009,000 131,590,000 125,504,000 94,151,000 93,862,000 97,409,000 56,352,000 74,237,000 74,222,000 76,949,000             55,104,250 81,532,000 64,492,000 74,393,000  
      yoy
    -47.88% -49.36% -43.08% -35.57% -30.38% -23.67% -13.47% -10.78% -7.06% -8.39% -4.18% -6.09% -7.24% -1.10% -4.19% -1.89% 1.95% 0.85% 11.64% 29.72% 50.75% 63.92% 63.59% 63.01% 35.09% 122.71% 26.82% 26.46% 26.59%                      
      qoq
    -12.93% -6.54% -26.04% -13.40% -15.40% 5.04% -16.28% -6.43% -7.25% 19.09% -13.67% -2.53% -8.57% 24.56% -15.40% -3.72% -2.52% 20.66% -13.37% 0.05% -3.57% 33.57% 0.66% 16.28% 4.85% 33.30% 0.31% -3.64% 72.86% -24.09% 0.02% -3.54%              -32.41% 26.42% -13.31%   
      cost of revenues
    25,374,000 30,999,000 31,701,000 35,478,000 53,973,000 45,599,000 43,420,000 45,411,000 46,497,000 45,804,000 83,575,000 47,412,000 49,150,000 51,424,000 45,203,000 45,684,000 55,085,000 55,710,000 67,102,000 60,708,000 71,384,000 57,133,000 62,370,000 43,524,000 42,390,000 26,165,000 22,164,000 20,518,000 23,335,000 14,481,500 19,918,000 17,784,000 20,224,000             43,090,500 68,281,000 38,596,000 65,485,000  
      gross profit
    37,888,000 41,660,000 46,041,000 69,642,000 67,414,000 97,885,000 93,173,000 117,736,000 127,853,000 142,183,000 74,279,000 135,441,000 138,451,000 153,769,000 119,536,000 149,037,000 147,159,000 151,757,000 104,840,000 137,770,000 126,994,000 148,588,000 91,648,000 109,485,000 89,200,000 99,339,000 71,987,000 73,344,000 74,074,000 73,606,000 54,319,000 56,438,000 56,725,000 54,126,000 40,284,000 39,275,000 41,206,000 42,485,000 32,644,000 31,629,000 27,731,000 41,774,000 19,566,000 30,805,000 19,379,000 45,794,000 13,251,000 25,896,000 8,908,000  
      yoy
    -43.80% -57.44% -50.59% -40.85% -47.27% -31.16% 25.44% -13.07% -7.65% -7.53% -37.86% -9.12% -5.92% 1.33% 14.02% 8.18% 15.88% 2.13% 14.39% 25.83% 42.37% 49.58% 27.31% 49.28% 20.42% 34.96% 32.53% 29.95% 30.58% 35.99% 34.84% 43.70% 37.66% 27.40% 23.40% 24.17% 48.59% 1.70% 66.84% 2.67% 43.10% -8.78% 47.66% 18.96% 117.55%      
      qoq
    -9.05% -9.52% -33.89% 3.30% -31.13% 5.06% -20.86% -7.91% -10.08% 91.42% -45.16% -2.17% -9.96% 28.64% -19.79% 1.28% -3.03% 44.75% -23.90% 8.49% -14.53% 62.13% -16.29% 22.74% -10.21% 38.00% -1.85% -0.99% 0.64% 35.51% -3.75% -0.51% 4.80% 34.36% 2.57% -4.69% -3.01% 30.15% 3.21% 14.06% -33.62% 113.50% -36.48% 58.96% -57.68% 245.59% -48.83% 190.70%   
      gross margin %
    59.89% 57.34% 59.22% 66.25% 55.54% 68.22% 68.21% 72.17% 73.33% 75.63% 47.06% 74.07% 73.80% 74.94% 72.56% 76.54% 72.76% 73.15% 60.97% 69.41% 64.02% 72.23% 59.50% 71.55% 67.79% 79.15% 76.46% 78.14% 76.04% 130.62% 73.17% 76.04% 73.72% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% Infinity% 83.10% 16.25% 40.15% 11.97%  
      operating expenses:
                                                      
      research and development
    9,139,000 16,958,000 18,350,000 28,717,000 29,428,000 41,008,000 41,337,000 43,651,000 44,435,000 45,724,000 46,202,000 52,872,000 46,907,000 46,316,000 45,426,000 52,480,000 52,415,000 47,826,000 43,269,000 41,595,000 46,131,000 46,949,000 44,041,000 40,374,000 39,541,000 38,573,000 36,442,000 32,065,000 32,692,000 33,495,000 29,045,000 26,218,000 25,533,000                  
      sales and marketing
    10,606,000 14,140,000 11,583,000 17,417,000 25,614,000 27,901,000 26,508,000 23,545,000 30,375,000 29,746,000 28,872,000 30,956,000 37,017,000 38,080,000 31,803,000 35,279,000 42,498,000 30,275,000 27,239,000 21,686,000 26,214,000 21,293,000 24,625,000 15,758,000 20,238,000 16,235,000 16,822,000 11,795,000 18,717,000 12,251,000 15,690,000 11,437,000 15,336,000 10,994,000 14,184,000 10,098,000 15,964,000 12,500,000 15,256,000 11,747,000 14,446,000 14,097,000 16,211,000 12,382,000 21,392,000 19,018,000 23,453,000 14,817,000 15,027,000  
      general and administrative
    19,180,000 44,834,000 33,232,000 59,966,000 39,374,000 56,296,000 51,910,000 54,016,000 55,534,000 53,426,000 57,075,000 70,309,000 58,973,000 61,700,000 53,742,000 53,935,000 46,870,000 47,459,000 33,971,000 39,719,000 37,870,000 31,128,000 40,784,000 31,292,000 26,145,000 27,445,000 23,752,000 22,622,000 23,670,000 19,979,000 20,000,000 19,479,000 18,256,000 17,248,000 17,320,000 14,501,000 15,342,000 14,232,000 13,905,000 14,569,000 12,666,000 9,429,000 12,060,000 11,943,000 11,777,000 10,357,000 10,986,000 10,654,000 9,840,000  
      impairment expense
        2,000,000  195,708,000 481,531,000                                           
      total operating expenses
    38,925,000 75,932,000 63,165,000 106,100,000 96,416,000 125,205,000 315,463,000 602,743,000 130,344,000 128,896,000 132,149,000 154,137,000 142,897,000 146,096,000 130,971,000 141,694,000 141,783,000 125,560,000 104,479,000 103,000,000 110,215,000 99,370,000 109,450,000 87,424,000 85,924,000 82,253,000 77,044,000 66,529,000 75,101,000 66,062,000 64,752,000 57,149,000 59,345,000 51,115,000 51,444,000 44,557,000 46,742,000 43,559,000 47,975,000 40,004,000 43,021,000 37,712,000 43,368,000 40,502,000 47,642,000 43,051,000 45,885,000 35,538,000 34,509,000  
      income from operations
    -1,037,000 -34,272,000 -17,124,000 -36,458,000 -29,002,000 -27,320,000 -222,290,000 -485,007,000 -2,491,000 13,287,000 -57,870,000 -18,696,000 -4,446,000 7,673,000 -11,435,000 7,343,000 5,376,000 26,197,000 361,000 34,770,000 16,779,000 49,218,000 -17,802,000 22,061,000 3,276,000 17,086,000 -5,057,000 6,815,000 -1,027,000 7,544,000 -10,433,000 -711,000 -2,620,000 3,011,000 -11,160,000 -5,282,000 -5,536,000 -1,074,000 -15,331,000 -8,375,000 -15,290,000 4,062,000 -23,802,000 -9,697,000 -28,263,000 2,743,000 -32,634,000 -9,642,000 -25,601,000  
      yoy
    -96.42% 25.45% -92.30% -92.48% 1064.27% -305.61% 284.12% 2494.18% -43.97% 73.17% 406.08% -354.61% -182.70% -70.71% -3267.59% -78.88% -67.96% -46.77% -102.03% 57.61% 412.18% 188.06% 252.03% 223.71% -418.99% 126.48% -51.53% -1058.51% -60.80% 150.55% -6.51% -86.54% -52.67% -380.35% -27.21% -36.93% -63.79% -126.44% -35.59% -13.63% -45.90% 48.09% -27.06% 0.57% 10.40%      
      qoq
    -96.97% 100.14% -53.03% 25.71% 6.16% -87.71% -54.17% 19370.37% -118.75% -122.96% 209.53% 320.51% -157.94% -167.10% -255.73% 36.59% -79.48% 7156.79% -98.96% 107.22% -65.91% -376.47% -180.69% 573.41% -80.83% -437.87% -174.20% -763.58% -113.61% -172.31% 1367.37% -72.86% -187.01% -126.98% 111.28% -4.59% 415.46% -92.99% 83.06% -45.23% -476.42% -117.07% 145.46% -65.69% -1130.37% -108.41% 238.46% -62.34%   
      operating margin %
    -1.64% -47.17% -22.03% -34.68% -23.89% -19.04% -162.74% -297.28% -1.43% 7.07% -36.66% -10.22% -2.37% 3.74% -6.94% 3.77% 2.66% 12.63% 0.21% 17.52% 8.46% 23.92% -11.56% 14.42% 2.49% 13.61% -5.37% 7.26% -1.05% 13.39% -14.05% -0.96% -3.40% Infinity% -Infinity% -Infinity% -Infinity% -Infinity% -Infinity% -Infinity% -Infinity% Infinity% -Infinity% -Infinity% -Infinity% 4.98% -40.03% -14.95% -34.41%  
      interest expense, net and other income, net:
                                                      
      interest expense
    -31,000 -41,000 -41,000 -41,000 -467,000 -631,000 -658,000 -651,000 -650,000 -658,000 -733,000 -1,114,000 -1,268,000 -1,302,000 -1,525,000 -1,616,000 -1,597,000 -1,633,000 -1,633,000 -1,701,000 -1,929,000 -21,977,000 -17,468,000 -13,425,000 -13,427,000 -13,557,000 -13,548,000 -13,514,000 -4,232,000 -3,769,000 -3,772,000 -3,664,000 -20,000 -18,000 -19,000 -18,000 -19,000 -20,000 -30,000 -61,000 -60,000 -65,000 -61,000 -60,000 -61,000 -62,000 -67,000 -127,000 -61,000  
      other income
    1,156,000 871,000 1,377,000 2,059,000 12,997,000 25,847,000 7,586,000 7,119,000 10,780,000 5,139,000 40,492,000 64,103,000 12,076,000 -4,218,000 97,258,000 1,809,000 6,180,000 1,146,000 8,670,000 1,920,000 -77,208,000 1,287,000 -804,000 3,240,000 4,960,000 5,492,000 7,751,000 5,253,000 1,567,000 1,320,000 1,209,000 894,000 564,000 507,000 261,000 -9,000 -199,000 -151,000 -148,000 -63,000 65,000 -1,000 85,000 56,000 76,000 62,000 541,000 156,000 120,000  
      total interest expense, net and other income
    1,125,000 830,000 1,336,000 2,018,000    6,468,000 10,130,000 4,481,000 39,759,000 62,989,000 10,808,000 -5,520,000 95,733,000 193,000 4,583,000 -487,000 7,037,000 219,000 -79,137,000 -20,690,000 -18,272,000 -10,185,000 -8,467,000 -8,065,000 -5,797,000                        
      income before benefit from income taxes
    88,000     -2,104,000 -215,362,000   17,768,000 -18,111,000   2,153,000 84,298,000                                 -9,613,000   
      benefit from income taxes
    140,000 -979,500 -1,683,000   -4,021,000 2,723,000   -8,103,000 -172,000   -295,000 167,264,000                                 -1,367,000   
      net income
    228,000 -32,803,000 -17,471,000 -35,663,000 -17,484,000 -6,125,000 -212,639,000 -616,884,000 -1,420,000 9,665,000 -18,283,000 24,612,000 2,186,000 1,858,000 251,562,000 7,476,000 5,742,000 24,306,000 6,651,000 32,764,000 -65,179,000 26,043,000 -37,140,000 10,589,000 -5,713,000 8,219,000 -11,477,000 -2,029,000 -4,318,000 5,347,000 -13,709,000 -3,909,000 -2,617,000 3,659,000 -11,516,000 -6,025,000 -6,401,000 -1,489,000 -16,063,000 -9,008,000 -15,685,000 3,630,000 -24,167,000 -10,131,000 -28,542,000 1,688,000 -32,441,000 -8,246,000 -25,759,000  
      yoy
    -101.30% 435.56% -91.78% -94.22% 1131.27% -163.37% 1063.04% -2606.44% -164.96% 420.18% -107.27% 229.21% -61.93% -92.36% 3682.32% -77.18% -108.81% -6.67% -117.91% 209.42% 1040.89% 216.86% 223.60% -621.88% 32.31% 53.71% -16.28% -48.09% 65.00% 46.13% 19.04% -35.12% -59.12% -345.74% -28.31% -33.12% -59.19% -141.02% -33.53% -11.08% -45.05% 115.05% -25.50% 22.86% 10.80%      
      qoq
    -100.70% 87.76% -51.01% 103.98% 185.45% -97.12% -65.53% 43342.54% -114.69% -152.86% -174.28% 1025.89% 17.65% -99.26% 3264.93% 30.20% -76.38% 265.45% -79.70% -150.27% -350.27% -170.12% -450.74% -285.35% -169.51% -171.61% 465.65% -53.01% -180.76% -139.00% 250.70% 49.37% -171.52% -131.77% 91.14% -5.87% 329.89% -90.73% 78.32% -42.57% -532.09% -115.02% 138.55% -64.50% -1790.88% -105.20% 293.41% -67.99%   
      net income margin %
    0.36% -45.15% -22.47% -33.93% -14.40% -4.27% -155.67% -378.12% -0.81% 5.14% -11.58% 13.46% 1.17% 0.91% 152.70% 3.84% 2.84% 11.72% 3.87% 16.51% -32.86% 12.66% -24.11% 6.92% -4.34% 6.55% -12.19% -2.16% -4.43% 9.49% -18.47% -5.27% -3.40% Infinity% -Infinity% -Infinity% -Infinity% -Infinity% -Infinity% -Infinity% -Infinity% Infinity% -Infinity% -Infinity% -Infinity% 3.06% -39.79% -12.79% -34.63%  
      net income per share
     -0.165 -0.16 -0.33 -0.17                -0.49 0.21 -0.29  -0.05 0.07 -0.1 -0.02 -0.04 0.05 -0.12 -0.03 -0.02 0.05 -0.11 -0.06 -0.07 -0.02 -0.17 -0.1 -0.18 0.05 -0.28 -0.12 -0.34 0.02 -0.39 -0.1 -0.31  
      basic
         -0.02 -2.05 -6.01 -0.01 0.09 -0.16 0.21 0.02 0.02 1.99 0.06 0.04 -0.045 0.05 0.23    0.09                           
      diluted
         -0.02 -2.05 -6.01 -0.01 -0.1 -0.16 -0.11 0.02 0.03 1.23 0.06 0.04 -0.045 0.05 0.2    0.08                           
      weighted-average shares used for eps calculation
      108,450 106,908 105,159             141,262   134,352 125,367 126,194  122,428 119,204 120,085 118,790 116,730 113,251 114,184 112,738 110,904 100,022 103,041 95,047 92,830 90,534 91,059 90,416 89,118 86,818 87,706 86,741 84,794 83,205 83,688 83,209 82,181  
      basic
    111,726 107,484    103,300 103,723 102,604 102,343 116,504 115,407 117,977 123,710 127,557 126,132 126,272 132,162  144,746 143,112    123,842                           
      diluted
    112,130 107,484    103,300 103,723 102,604 102,343 128,569 115,407 132,944 124,304 149,859 148,045 149,574 133,270  146,699 168,282    133,851                           
      income before provision for income taxes
     -33,442,000 -15,788,000 -34,440,000 -16,472,000   -478,539,000 7,639,000   44,293,000 6,362,000   7,536,000 9,959,000 25,710,000 7,398,000 34,989,000 -62,358,000 28,528,000 -36,074,000 11,876,000 -5,191,000 9,021,000 -10,854,000 -1,446,000 -3,692,000 5,095,000 -12,996,000 -3,481,000 -2,076,000 3,500,000 -10,918,000 -5,309,000 -5,754,000 -1,245,000 -15,509,000 -8,499,000 -15,285,000 3,996,000 -23,778,000 -9,701,000 -28,248,000 -16,828,750 -32,160,000  -25,542,000  
      net income per share
     -0.165 -0.16 -0.33 -0.17                -0.49 0.21 -0.29  -0.05 0.07 -0.1 -0.02 -0.04 0.05 -0.12 -0.03 -0.02 0.05 -0.11 -0.06 -0.07 -0.02 -0.17 -0.1 -0.18 0.05 -0.28 -0.12 -0.34 0.02 -0.39 -0.1 -0.31  
      weighted-average shares used for eps calculation
      108,450 106,908 105,159             141,262   134,352 125,367 126,194  122,428 119,204 120,085 118,790 116,730 113,251 114,184 112,738 110,904 100,022 103,041 95,047 92,830 90,534 91,059 90,416 89,118 86,818 87,706 86,741 84,794 83,205 83,688 83,209 82,181  
      provision for income taxes
       -1,223,000 -1,012,000   -138,345,000 -9,059,000   -19,681,000 -4,176,000   -60,000 -4,217,000 1,404,000 747,000 2,225,000 2,821,000 2,485,000 1,066,000 1,287,000 522,000 802,000 623,000 583,000 626,000 -252,000 713,000 428,000 541,000 -159,000 598,000 716,000 647,000 244,000 554,000 509,000 400,000 366,000 389,000 430,000 294,000 -217,250 281,000  217,000  
      interest expense and other income, net:
                                                      
      total interest expense and other income
        12,530,000 5,881,500 6,928,000                     -8,261,000 -2,665,000 -1,197,250 -2,563,000 -2,770,000 544,000 -750 242,000 -27,000 -218,000 -74,250 -178,000 -124,000 5,000 -66,000 24,000 -4,000 15,000      
      restructuring charges
                              28,000 47,000 22,000 337,000 17,000 15,000 220,000 24,000 64,000 59,000 900,000     1,548,000 342,000 464,000 2,514,000      
      gain on liquidation of textbooks
                                        -4,766,000    -1,005,000 -1,677,000 -909,000  -4,185,000 1,289,000 -2,044,000  -1,678,000  
      net revenues:
                                                      
      rental
                                         7,756,000 5,511,000 12,006,000 14,564,000 27,166,000 22,703,000 32,782,000 37,714,000      
      services
                                     73,507,000 62,640,000 56,317,000 62,602,000 54,469,000 49,765,000 37,668,000 39,362,000 37,995,000 33,358,000 29,276,000 31,367,000      
      sales
                                         832,000 16,067,000 3,362,000 12,728,000 2,993,000 25,225,000 5,003,000 15,791,000      
      total net revenues
                                     73,507,000 62,640,000 56,317,000 62,602,000 63,057,000 71,343,000 53,036,000 66,654,000 68,154,000 81,286,000 67,061,000 84,872,000      
      cost of revenues:
                                                      
      total cost of revenues
                                     19,381,000 22,356,000 17,042,000 21,396,000 20,572,000 38,699,000 21,407,000 38,923,000 26,380,000 61,720,000 36,256,000 65,493,000      
      technology and development
                                     22,849,000 19,876,000 19,899,000 19,302,000 17,099,000 16,241,000 16,033,000 16,958,000 14,315,000 15,664,000 13,268,000 16,144,000 12,387,000 13,490,000 12,189,000 11,320,000  
      loss on liquidation of textbooks
                                     -1,191,500    -130,750 2,673,000 -2,191,000    2,445,000       
      restructuring (credits) charges
                                         -125,000 -100,000 -154,000 -44,000          
      interest and other income, net:
                                                      
      total interest and other income
                                                  474,000 29,000 59,000  
      (gain) loss on liquidation of textbooks
                                                   -2,122,000   
    Balance Sheets:
    Quarterly
    Annual
      Unit: USD2026-03-31 2025-12-31 2025-09-30 2025-06-30 2025-03-31 2024-12-31 2024-09-30 2024-06-30 2024-03-31 2023-12-31 2023-09-30 2023-06-30 2023-03-31 2022-12-31 2022-09-30 2022-06-30 2022-03-31 2021-12-31 2021-09-30 2021-06-30 2021-03-31 2020-12-31 2020-09-30 2020-06-30 2020-03-31 2019-12-31 2019-09-30 2019-06-30 2019-03-31 2018-12-31 2018-09-30 2018-06-30 2018-03-31 2017-12-31 2017-09-30 2017-06-30 2017-03-31 2016-12-31 2016-09-30 2016-06-30 2016-03-31 2015-12-31 2015-09-30 2015-06-30 2015-03-31 2014-12-31 2014-09-30 2014-06-30 2014-03-31 2013-12-31 
                                                        
        assets
                                                        
        current assets
                                                        
        cash and cash equivalents
      33,526,000 31,146,000 38,180,000 36,825,000 44,105,000 161,475,000 152,073,000 133,068,000 143,747,000 135,757,000 94,419,000 175,368,000 281,302,000 473,677,000 69,349,000 402,089,000 267,731,000 854,078,000 713,837,000 840,056,000 656,168,000 479,853,000 527,541,000 285,064,000 359,101,000 387,520,000 450,457,000 555,792,000 914,500,000 374,664,000 379,020,000 384,926,000 106,827,000 126,457,000 122,227,000   77,329,000 90,213,000 49,679,000 41,504,000 67,029,000 80,941,000 35,087,000 50,028,000 56,117,000 53,186,000 30,783,000 39,440,000 76,864,000 
        short-term investments
      32,388,000 41,674,000 58,209,000 48,815,000 44,188,000 154,249,000 209,003,000 212,396,000 247,013,000 194,257,000 166,841,000 209,686,000 277,864,000 583,973,000 871,408,000 981,288,000 915,431,000 691,781,000 1,038,345,000 1,221,666,000 1,215,944,000 665,567,000 723,327,000 417,530,000 404,794,000 381,074,000 345,392,000 259,399,000 70,080,000 93,345,000 80,898,000 80,938,000 82,264,000 81,742,000 80,914,000      20,002,000 17,800,000 21,365,000 27,409,000 28,867,000 33,346,000 30,035,000 28,430,000 54,376,000 37,071,000 
        accounts receivable
      17,795,000 15,604,000 15,440,000 18,055,000 28,549,000 23,641,000 23,749,000 20,964,000 24,741,000 31,404,000 30,480,000 20,670,000 22,000,000 23,515,000 22,187,000 16,815,000 19,918,000 17,850,000 9,302,000 10,091,000 11,633,000 12,913,000 12,487,000 8,834,000 6,493,000 11,529,000 13,678,000 5,948,000 8,870,000 12,733,000 8,620,000 8,096,000 8,055,000 10,855,000 9,843,000 8,750,000 8,787,000 9,206,000 9,481,000 12,919,000 10,955,000 13,157,000 9,323,000 12,131,000 10,674,000 14,396,000 15,758,000 9,913,000 9,345,000 7,091,000 
        prepaid expenses
      12,128,000 16,331,000 18,742,000 23,683,000 14,514,000 17,100,000 24,706,000 30,841,000 20,429,000 20,980,000 30,761,000 18,620,000 25,486,000 28,481,000 33,441,000 20,115,000 28,882,000 35,093,000 35,164,000 18,811,000 25,256,000 12,776,000 15,082,000 16,060,000 17,852,000 10,538,000 9,654,000 12,152,000 15,739,000 4,673,000 7,099,000 8,707,000 10,799,000 2,043,000 3,865,000 6,950,000 8,197,000 2,579,000 4,018,000 5,608,000 8,477,000 3,117,000 5,786,000 7,657,000 8,611,000 3,091,000 3,391,000 3,652,000 3,025,000 2,134,000 
        other current assets
      14,948,000 16,857,000 72,788,000 76,548,000 78,395,000 81,094,000 86,980,000 36,279,000 30,010,000 32,437,000 25,195,000 22,372,000 30,832,000 34,754,000 35,196,000 31,559,000 14,671,000 23,846,000 29,316,000 25,643,000 26,625,000 11,846,000 21,059,000 14,650,000 19,528,000 16,606,000 24,888,000 14,608,000 9,691,000 9,510,000 26,651,000 7,742,000 6,898,000 7,845,000 23,955,000 7,571,000 16,637,000 22,259,000 35,570,000 40,224,000 43,192,000 31,732,000 33,834,000 16,872,000 3,986,000 3,864,000 8,679,000 1,774,000 2,181,000 1,112,000 
        total current assets
      110,785,000 121,612,000 203,359,000 203,926,000 209,751,000 437,559,000 496,511,000 433,548,000 465,940,000 414,835,000 347,696,000 446,716,000 637,484,000 1,144,400,000 1,031,581,000 1,451,866,000 1,246,633,000 1,622,648,000 1,825,964,000 2,116,267,000 1,935,626,000 1,182,955,000 1,299,496,000 742,138,000 807,768,000 807,267,000 844,069,000 847,899,000 1,018,880,000 494,925,000 502,288,000 490,409,000 214,843,000 228,942,000 240,804,000 89,357,000 103,915,000 111,373,000 139,282,000 108,430,000 124,130,000 132,835,000 151,249,000 99,156,000 102,166,000 110,814,000 111,049,000 74,552,000 108,406,000 124,309,000 
        long-term investments
      1,984,000 12,392,000 15,277,000 28,474,000 38,093,000 212,650,000 270,161,000 259,925,000 221,665,000 249,547,000 412,541,000 422,758,000 613,863,000 216,233,000 286,781,000 265,729,000 435,413,000 745,993,000 813,500,000 484,853,000 711,224,000 523,628,000 521,261,000 280,492,000 273,114,000 310,483,000 340,118,000 288,682,000 12,533,000 16,052,000 14,961,000 15,957,000 10,628,000 20,305,000 17,013,000      2,878,000 4,229,000 2,935,000 4,727,000  1,451,000 14,124,000 19,295,000 36,671,000 24,320,000 
        property and equipment
      105,127,000 115,168,000 125,598,000 135,491,000 144,971,000 170,648,000 177,882,000 179,278,000 188,430,000 183,073,000 168,735,000 198,318,000 201,305,000 204,383,000 202,362,000 195,370,000 187,743,000 169,938,000 156,121,000 149,627,000 134,093,000 125,807,000 113,058,000 105,640,000 97,889,000 87,359,000 77,667,000 76,962,000 72,937,000 59,904,000 52,945,000 51,516,000 48,197,000 47,493,000 45,078,000 40,294,000 36,778,000 35,305,000 30,766,000 29,356,000 23,361,000 19,971,000 18,537,000 18,569,000 17,892,000 18,369,000 18,298,000 18,933,000 18,994,000 18,964,000 
        intangible assets
      4,964,000 6,041,000 7,117,000 8,194,000 9,271,000 10,347,000 11,424,000 12,848,000 48,143,000 52,430,000 56,638,000 67,630,000 73,086,000 78,333,000 80,646,000 91,469,000 102,685,000 40,566,000 43,573,000 46,620,000 49,798,000 51,249,000 55,386,000 59,522,000 32,075,000 34,667,000 20,622,000 22,374,000 24,097,000 25,915,000 27,813,000 22,591,000 19,902,000 21,153,000 16,599,000 17,970,000 19,345,000 20,748,000 21,659,000 23,061,000 8,237,000 8,865,000 9,511,000 10,629,000 12,066,000 13,626,000 10,972,000 12,664,000 3,150,000 3,311,000 
        right of use assets
      12,113,000 13,188,000 18,088,000 19,418,000 21,479,000 22,256,000 29,071,000 21,508,000 23,521,000 25,130,000 26,568,000 28,267,000 29,770,000 18,838,000 18,144,000 15,485,000 18,879,000 18,062,000 19,520,000 21,100,000 22,617,000 24,226,000 14,124,000 15,207,000 14,608,000 15,931,000 16,312,000 14,756,000 15,875,000                      
        other assets
      9,129,000 9,613,000 8,832,000 8,950,000 15,204,000 14,527,000 15,315,000 15,167,000 15,961,000 28,382,000 28,964,000 28,492,000 19,824,000 20,612,000 21,680,000 17,951,000 19,182,000 21,035,000 22,484,000 24,073,000 25,602,000 24,030,000 18,948,000 25,068,000 23,554,000 18,778,000 15,836,000 15,544,000 15,412,000 14,618,000 4,523,000 4,256,000 4,383,000 3,765,000 4,419,000 4,297,000 4,699,000 4,412,000 5,565,000 5,227,000 4,169,000 4,427,000 3,882,000 1,922,000 1,732,000 1,804,000 1,800,000 2,160,000 2,024,000 1,814,000 
        total assets
      244,102,000 278,014,000 378,271,000 404,453,000 438,769,000 868,951,000 1,002,672,000 1,114,330,000 1,732,644,000 1,727,235,000 1,804,639,000 1,968,535,000 2,361,787,000 2,465,416,000 2,397,861,000 2,654,519,000 2,662,470,000 2,919,246,000 3,187,495,000 3,150,947,000 3,193,561,000 2,251,258,000 2,341,657,000 1,539,878,000 1,495,004,000 1,488,998,000 1,463,692,000 1,415,683,000 1,309,215,000 760,938,000 752,292,000 720,571,000 423,478,000 446,930,000 440,152,000 268,157,000 280,976,000 290,652,000 316,208,000 292,888,000 274,716,000 291,356,000 322,057,000 287,564,000 309,728,000 318,127,000 348,133,000 314,522,000 332,765,000 327,371,000 
        liabilities and stockholders' equity
                                                        
        current liabilities
                                                        
        accounts payable
      7,081,000 3,258,000 8,850,000 8,321,000 16,812,000 15,159,000 18,124,000 14,424,000 20,119,000 28,184,000 18,187,000 12,954,000 13,058,000 12,367,000 14,902,000 11,910,000 9,549,000 11,992,000 10,518,000 6,211,000 14,902,000 8,547,000 5,838,000 6,421,000 13,605,000 7,362,000 4,197,000 3,131,000 6,341,000 8,177,000 4,283,000 5,337,000 3,981,000 7,049,000 2,109,000 809,000 3,261,000 5,175,000 7,992,000 6,260,000 4,307,000 5,860,000 11,982,000 3,832,000 4,846,000 10,945,000 6,063,000 9,813,000 3,742,000 4,078,000 
        deferred revenue
      28,753,000 29,675,000 32,148,000 34,759,000 45,150,000 39,217,000 44,355,000 45,023,000 54,056,000 55,336,000 58,906,000 53,200,000 58,568,000 56,273,000 60,475,000 53,297,000 60,458,000 35,143,000 49,983,000 34,682,000 48,608,000 32,620,000 51,941,000 28,320,000 35,753,000 18,780,000 27,457,000 18,821,000 26,276,000 17,418,000 25,281,000 13,710,000 18,625,000 13,440,000 21,906,000 12,457,000 18,106,000 14,836,000 30,004,000 14,458,000 26,769,000 14,971,000 46,081,000 19,752,000 44,969,000 24,591,000 72,462,000 24,175,000 52,116,000 22,804,000 
        accrued liabilities
      37,285,000 54,249,000 111,048,000 121,373,000 109,070,000 115,360,000 125,138,000 68,001,000 73,555,000 77,863,000 73,133,000 76,657,000 68,026,000 70,234,000 68,096,000 69,160,000 85,424,000 67,209,000 73,320,000 72,644,000 78,089,000 61,962,000 79,524,000 50,067,000 47,241,000 39,964,000 52,199,000 37,425,000 35,706,000 34,077,000 46,999,000 29,460,000 26,418,000 31,074,000 41,940,000 27,861,000 41,005,000 44,319,000 59,034,000 46,427,000 19,274,000 35,280,000 39,674,000 23,903,000 20,187,000 31,183,000 29,563,000 19,991,000 19,826,000 21,270,000 
        current portion of convertible senior notes
      33,822,000 53,765,000 62,558,000 62,516,000  358,605,000 358,222,000 357,838,000 357,458,000 357,079,000           109,494,000                              
        total current liabilities
      106,941,000 140,947,000 214,604,000 226,969,000 171,032,000 528,341,000 545,839,000 485,286,000 505,188,000 518,462,000 150,226,000 142,811,000 139,652,000 138,874,000 143,473,000 134,367,000 155,431,000 114,344,000 133,821,000 113,537,000 251,093,000 109,732,000 142,955,000 90,493,000 101,833,000 71,389,000 88,835,000 64,151,000 72,963,000 59,672,000 76,563,000 48,507,000 49,024,000 51,563,000 65,955,000 41,127,000 62,372,000 64,330,000 97,030,000 67,145,000 50,350,000 56,111,000 97,737,000 47,487,000 70,002,000 66,719,000 108,088,000 53,979,000 75,684,000 48,152,000 
        long-term liabilities
                                                        
        long-term operating lease liabilities
      13,677,000 15,205,000 15,355,000 17,700,000 17,797,000 18,509,000 23,665,000 15,595,000 16,460,000 18,063,000 19,537,000 21,253,000 23,064,000 13,375,000 12,347,000 11,281,000 12,456,000 12,447,000 14,137,000 15,811,000 17,551,000 19,264,000 11,661,000 12,947,000 13,012,000 14,513,000 15,315,000 14,243,000 15,424,000                      
        other long-term liabilities
      2,341,000 2,239,000 2,259,000 1,928,000 1,794,000 1,776,000 4,945,000 4,870,000 4,603,000 3,334,000 2,236,000 2,427,000 2,662,000 7,985,000 7,996,000 9,149,000 6,528,000 7,383,000 8,271,000 8,377,000 7,628,000 5,705,000 4,665,000 11,867,000 3,983,000 3,964,000 3,815,000 3,592,000 3,311,000 6,964,000 7,016,000 6,767,000                   
        total long-term liabilities
      16,018,000 17,444,000 17,614,000 19,628,000 82,066,000 147,629,000 271,852,000 263,544,000 263,982,000 264,155,000 621,064,000 790,723,000 1,215,376,000 1,209,953,000 1,207,856,000 1,701,361,000 1,698,518,000 1,697,985,000 1,699,157,000 1,699,528,000 1,699,125,000 1,531,891,000 1,553,310,000 951,007,000 930,244,000 918,780,000 906,345,000 891,961,000 808,115,000 290,632,000 287,148,000 283,345,000             4,285,000 4,365,000 5,315,000 5,187,000 5,153,000 4,979,000 
        total liabilities
      122,959,000 158,391,000 232,218,000 246,597,000 253,098,000 675,970,000 817,691,000 748,830,000 769,170,000 782,617,000 771,290,000 933,534,000 1,355,028,000 1,348,827,000 1,351,329,000 1,835,728,000 1,853,949,000 1,812,329,000 1,832,978,000 1,813,065,000 1,950,218,000 1,641,623,000 1,696,265,000 1,041,500,000 1,032,077,000 990,169,000 995,180,000 956,112,000 881,078,000 350,304,000 363,711,000 331,852,000 53,467,000 55,868,000 71,198,000 46,101,000 66,914,000 68,713,000 101,105,000 71,155,000 54,319,000 60,281,000 101,998,000 52,219,000 74,287,000 71,084,000 113,403,000 59,166,000 80,837,000 53,131,000 
        commitments and contingencies
                                                        
        stockholders' equity:
                                                        
        preferred stock, 0.001 par value per share...
                                                        
        common stock, 0.001 par value per share...
      112,000  109,000 108,000 105,000  104,000 103,000 102,000  116,000 115,000 120,000  125,000 126,000 127,000  145,000 145,000                               
        additional paid-in capital
      1,147,586,000 1,145,371,000 1,139,266,000 1,133,686,000 1,125,738,000 1,114,550,000 1,098,242,000 1,075,989,000 1,057,837,000 1,031,627,000 1,151,697,000 1,121,820,000 1,120,344,000 1,244,504,000 1,220,688,000 1,211,506,000 1,176,765,000 1,449,305,000 1,717,421,000 1,706,855,000 1,645,352,000 1,030,577,000 1,092,574,000 907,908,000 890,258,000 916,095,000 894,660,000 873,104,000 839,924,000 818,113,000 801,355,000 787,480,000 764,065,000 782,845,000 764,097,000 605,638,000 591,774,000 593,351,000 584,999,000 575,601,000 565,179,000 560,242,000 552,773,000 543,789,000 533,739,000 516,845,000 506,208,000 494,364,000 482,718,000  
        accumulated other comprehensive loss
      -33,921,000 -32,997,000 -33,263,000 -33,350,000 -33,247,000 -32,233,000 -30,049,000 -39,915,000 -40,672,000 -34,739,000 -56,426,000 -43,179,000 -45,338,000 -57,488,000 -101,870,000 -68,868,000 -36,922,000        -5,362,000 -1,096,000 -1,758,000 -618,000 -900,000 -1,019,000 -965,000 -661,000  -282,000   -77,000 -176,000 -148,000 -183,000 -104,000 -172,000 -89,000   -13,000 -1,000    
        accumulated deficit
      -992,634,000 -992,862,000 -960,059,000 -942,588,000 -906,925,000 -889,441,000 -883,316,000 -670,677,000 -53,793,000 -52,373,000 -62,038,000 -43,755,000 -68,367,000 -70,553,000 -72,411,000 -323,973,000 -331,449,000 -337,191,000 -361,497,000 -368,148,000 -400,912,000 -422,601,000 -448,644,000 -411,504,000 -422,093,000 -416,292,000 -424,511,000 -413,034,000 -411,005,000 -406,576,000 -411,924,000 -398,214,000 -394,305,000 -391,611,000 -395,270,000 -383,754,000 -377,729,000 -371,328,000 -369,839,000 -353,776,000 -344,768,000 -329,083,000 -332,713,000 -308,546,000 -298,415,000 -269,873,000 -271,561,000 -239,120,000 -230,874,000 -205,115,000 
        total stockholders' equity
      121,143,000  146,053,000 157,856,000 185,671,000  184,981,000 365,500,000 963,474,000  1,033,349,000 1,035,001,000 1,006,759,000  1,046,532,000 818,791,000 808,521,000  1,354,517,000 1,337,882,000 1,243,343,000  645,392,000 498,378,000 462,927,000 498,829,000 468,512,000 459,571,000 428,137,000 410,634,000 388,581,000 388,719,000 370,011,000 391,062,000 368,954,000 222,056,000 214,062,000 221,939,000 215,103,000 221,733,000 220,397,000 231,075,000 220,059,000 235,345,000 235,441,000 247,043,000 234,730,000 255,356,000 251,928,000  
        total liabilities and stockholders' equity
      244,102,000  378,271,000 404,453,000 438,769,000  1,002,672,000 1,114,330,000 1,732,644,000  1,804,639,000 1,968,535,000 2,361,787,000  2,397,861,000 2,654,519,000 2,662,470,000  3,187,495,000 3,150,947,000 3,193,561,000  2,341,657,000 1,539,878,000 1,495,004,000 1,488,998,000 1,463,692,000 1,415,683,000 1,309,215,000 760,938,000 752,292,000 720,571,000 423,478,000 446,930,000 440,152,000 268,157,000 280,976,000 290,652,000 316,208,000 292,888,000 274,716,000 291,356,000 322,057,000 287,564,000 309,728,000 318,127,000 348,133,000 314,522,000 332,765,000  
        liabilities and stockholders’ equity
                                                        
        convertible senior notes
          62,475,000 127,344,000 243,242,000 243,079,000 242,919,000 242,758,000 599,291,000 767,043,000 1,189,650,000 1,188,593,000 1,187,513,000 1,680,931,000 1,679,534,000 1,678,155,000 1,676,749,000 1,675,340,000  1,506,922,000 1,536,984,000 926,193,000 913,249,000 900,303,000 887,215,000 874,126,000 789,380,000 283,668,000 280,132,000 276,578,000                   
        stockholders’ equity:
                                                        
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at december 31, 2025 and december 31, 2024
                                                        
        common stock
       111,000    105,000    103,000    126,000    137,000   141,000 129,000 129,000 124,000 124,000 122,000 121,000 119,000 118,000 116,000 115,000 114,000 113,000 110,000 108,000 96,000 94,000 92,000 91,000 91,000 90,000 88,000 88,000 88,000 86,000 84,000 84,000 84,000 83,000 82,000 
        total stockholders’ equity
       119,623,000    192,981,000    944,618,000    1,116,589,000    1,106,917,000    609,635,000                            274,240,000 
        total liabilities and stockholders’ equity
       278,014,000    868,951,000    1,727,235,000    2,465,416,000    2,919,246,000    2,251,258,000                             
        goodwill
             189,769,000 628,784,000 631,995,000 617,690,000 629,564,000 622,679,000 615,093,000 589,702,000 616,649,000 641,284,000 289,763,000 290,499,000 290,725,000 290,601,000 285,214,000 284,809,000 284,682,000 214,323,000 214,513,000 149,068,000 149,466,000 149,481,000 149,524,000 149,762,000 135,842,000 125,525,000 125,272,000 116,239,000 116,239,000 116,239,000 116,239,000 114,980,000 114,980,000 91,301,000 91,301,000 91,301,000 91,301,000 91,301,000 91,301,000 86,685,000 86,685,000 49,605,000 49,545,000 
        deferred tax assets
           964,000 2,308,000 2,287,000 140,200,000 141,843,000 145,807,000 146,790,000 163,776,000 167,524,000 166,965,000                                  39,000 37,000 
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at december 31, 2024 and december 31, 2023
                                                        
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at december 31, 2023 and december 31, 2022
                                                        
        textbook library
                      10,651,000 11,241,000 15,834,000 17,682,000 24,000,000 34,149,000 34,575,000 27,129,000 31,673,000             2,575,000 3,956,000 11,834,000 20,640,000 29,728,000 44,642,000 61,260,000 84,571,000 80,762,000 105,205,000 100,233,000 113,915,000 105,108,000 
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at december 31, 2022 and december 31, 2021
                                                        
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at december 31, 2021 and december 31, 2020
                                                        
        accumulated other comprehensive income
                       -5,334,000 -1,552,000 -970,000 -1,238,000 1,530,000 1,333,000 1,850,000         138,000  19,000 76,000            28,000 1,000 -6,000 
        long-term portion of convertible senior notes
                          1,673,946,000                              
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding
                                                        
        current operating lease liabilities
                           6,603,000 5,652,000 5,685,000 5,234,000 5,283,000 4,982,000 4,774,000 4,640,000                      
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at december 31, 2020 and december 31, 2019
                                                        
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at december 31, 2019 and december 31, 2018
                                                        
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at december 31, 2018 and december 31, 2017
                                                        
        total other long-term liabilities
                                      4,443,000 4,305,000 5,243,000 4,974,000 4,542,000 4,383,000 4,075,000 4,010,000 3,969,000 4,170,000 4,261,000 4,732,000       
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at december 31, 2017 and december 31, 2016
                                                        
        cash
                                         66,086,000 70,294,000              
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at december 31, 2016 and december 31, 2015
                                                        
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at september 30, 2015 and december 31, 2014
                                                        
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at june 30, 2015 and december 31, 2014, respectively
                                                        
        accumulated other comprehensive gain
                                                 14,000 31,000      
        current assets:
                                                        
        current liabilities:
                                                        
        long-term liabilities:
                                                        
        other liabilities
                                                  4,285,000 4,365,000 5,315,000 5,187,000 5,153,000 4,979,000 
        preferred stock, 0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding at march 31, 2015 and december 31, 2014, respectively
                                                        
        preferred stock, 0.001 par value –10,000,000 shares authorized, no shares issued andoutstanding at december 31, 2014 and 2013, respectively
                                                        
        preferred stock, 0.001 par value –10,000,000 shares authorized, no shares issued and outstanding at september 30, 2014 and december 31, 2013, respectively
                                                        
        preferred stock, 0.001 par value –10,000,000 shares authorized, no shares issued and outstanding at june 30, 2014 and december 31, 2013, respectively
                                                        
        preferred stock, 0.001 par value –10,000,000 shares authorized, no shares issued and outstanding at march 31, 2014 and december 31, 2013, respectively
                                                        
        liabilities, convertible preferred stock and stockholders’ equity
                                                        
        preferred stock warrant liabilities
                                                        
        debt obligations, current
                                                        
        deferred tax liabilities
                                                        
        convertible preferred stock, 0.001 par value –no shares authorized, issued and outstanding, and aggregate liquidation preference of 0 as of december 31, 2013; 76,388,007 shares authorized, 62,814,746 shares issued and outstanding, and aggregate liquidation preference of 210,845 as of december 31, 2012
                                                        
        stockholders’ equity
                                                        
        preferred stock, 0.001 par value –10,000,000 shares authorized, no shares issued and outstanding at december 31, 2013; no shares authorized, issued or outstanding at december 31, 2012
                                                        
        additional paid-in capital common stock
                                                       479,279,000 
        total liabilities, convertible preferred stock and stockholders’ equity
                                                       327,371,000 
      Cashflow Statements:
      Quarterly
      Annual
        Unit: USD2026-03-31 2025-12-31 2025-09-30 2025-06-30 2025-03-31 2024-12-31 2024-09-30 2024-06-30 2024-03-31 2023-12-31 2023-09-30 2023-06-30 2023-03-31 2022-12-31 2022-09-30 2022-06-30 2022-03-31 2021-12-31 2021-09-30 2021-06-30 2021-03-31 2020-12-31 2020-09-30 2020-06-30 2020-03-31 2019-12-31 2019-09-30 2019-06-30 2019-03-31 2018-12-31 2018-09-30 2018-06-30 2018-03-31 2017-12-31 2017-09-30 2017-06-30 2017-03-31 2016-12-31 2016-09-30 2016-06-30 2016-03-31 2015-12-31 2015-09-30 2015-06-30 2015-03-31 2014-12-31 2014-09-30 2014-06-30 2014-03-31 
                                                         
          cash flows from operating activities
                                                         
          net income
        228,000     -6,125,000 -212,639,000 -616,884,000 -1,420,000 9,665,000 -18,283,000 24,612,000 2,186,000 1,858,000 251,562,000 7,476,000 5,742,000                                 
          adjustments to reconcile net income to net cash from operating activities:
                                                         
          share-based compensation expense
        2,711,000 6,770,000 5,925,000 7,912,000 11,257,000 15,347,000 21,931,000 18,047,000 29,289,000 31,906,000 31,930,000 35,920,000 33,746,000 35,115,000 34,170,000 31,087,000 33,084,000 32,689,000 24,512,000 28,545,000 23,100,000 24,646,000 21,529,000 19,546,000 18,334,000 17,554,000 16,865,000 15,452,000 15,038,000 14,527,000 13,818,000 12,043,000 11,642,000 10,891,000 10,091,000 9,099,000 8,278,000 9,084,000 10,210,000 11,221,000 11,270,000 6,991,000 8,933,000 7,831,000 15,020,000     
          depreciation and amortization expense
        13,947,000 14,996,000 15,321,000 16,226,000 32,094,000 19,378,000 19,573,000 19,706,000 19,687,000                 8,878,000 7,435,000 7,149,000 6,785,000 6,174,000 5,966,000 5,448,000 5,217,000                 
          deferred tax assets
        -95,000 1,029,000 170,000 134,000 15,000                                             
          operating lease expense, net of accretion
        545,000 758,000 864,000 930,000 1,089,000        1,496,000 1,581,000 1,504,000 1,602,000 1,640,000 1,467,000 1,463,000 1,475,000 1,589,000 1,501,000 1,215,000 1,132,000 1,053,000 1,101,000 1,116,000 1,119,000 1,049,000                     
          amortization of debt issuance costs
        31,000 41,000 41,000 41,000 377,000 519,000 547,000 540,000 541,000 546,000 622,000 931,000 1,057,000  1,305,000 1,397,000 1,382,000                                 
          loss from write-offs of property and equipment
        49,000 1,166,000 235,000 -1,729,000 2,287,000                                             
          gain on early extinguishment of debt
        -523,000  -7,360,000      -32,149,000                                       
          realized gain on sale of investments
        -5,000  -752,000                                             
          other non-cash items
        -159,000 374,000 724,000 353,000 -28,000 434,000 140,000 113,000 -31,000 -839,000 694,000 -1,078,000 -5,000 -241,000 452,000 904,000 -737,000 -1,471,000 200,000 211,000 87,000 -33,000 104,000 -188,000 -1,000  -255,000 -71,000 -44,000  -64,000 156,000 -41,000  117,000 -9,000 -46,000  124,000 -41,000 23,000         
          change in assets and liabilities:
                                                         
          accounts receivable
        -2,338,000 -153,000 2,478,000 10,807,000 -4,693,000 -248,000 -2,542,000 3,856,000 6,705,000 -891,000 -9,989,000 1,503,000 1,578,000 -1,493,000 -5,486,000 2,935,000 292,000 -8,597,000 131,000 1,222,000 2,240,000 -506,000 -3,855,000 -968,000 4,929,000 2,679,000 -7,794,000 2,920,000 4,024,000 -3,947,000 -200,000 -174,000 2,783,000 -961,000 -1,203,000 42,000 1,947,000 -439,000 -2,295,000 446,000 2,161,000 1,111,000 -515,000 -2,318,000 2,434,000 1,924,000 -1,422,000 16,000 -2,227,000 
          prepaid expenses and other current assets
        6,018,000 58,548,000 8,763,000 -6,821,000 5,880,000 13,993,000 -43,552,000 -15,756,000 3,583,000 2,918,000 -14,524,000 6,597,000 8,485,000 3,940,000 -15,517,000 7,046,000 21,722,000 9,216,000 -16,355,000 10,360,000 -25,075,000 11,597,000 -4,366,000 7,895,000 -9,707,000 7,811,000 -7,799,000 -1,420,000 -11,522,000 19,329,000 -17,477,000 1,121,000 -7,894,000 17,843,000 -13,365,000 10,313,000 -1,241,000 14,751,000 6,196,000 5,908,000 -16,816,000 4,625,000 -15,098,000 -11,807,000 -5,598,000 5,375,000 -6,582,000 128,000 -1,902,000 
          other assets
        -268,000 -1,302,000 395,000 410,000 518,000 1,599,000 304,000 497,000 -1,270,000 2,158,000 3,201,000 2,667,000 2,803,000 -1,363,000 2,868,000 4,716,000 8,342,000 6,915,000 2,252,000 6,162,000 1,058,000 -1,576,000 -1,926,000 713,000 -1,425,000 -3,483,000 -345,000 3,500,000 -1,166,000 635,000 -87,000 6,000 -506,000 654,000 -122,000 402,000 -287,000 1,153,000 682,000 -656,000 258,000 -388,000 49,000 -300,000 47,000 -8,000 323,000 -229,000 -241,000 
          accounts payable
        3,599,000 -4,683,000 1,061,000 -7,573,000 1,535,000 -4,068,000 3,737,000 -5,456,000 -6,589,000 8,237,000 5,491,000 -335,000 -336,000 -2,416,000 3,518,000 2,288,000 -7,534,000 1,421,000 4,959,000 -9,736,000 6,597,000 2,753,000 -1,060,000 -138,000 -436,000 1,588,000 1,434,000 -3,581,000 -1,836,000 3,894,000 -1,289,000 1,356,000 -3,068,000 4,940,000 1,300,000 -2,452,000 -1,139,000 -3,441,000 1,697,000 2,625,000 -1,609,000 -6,213,000 8,127,000 -1,212,000 -4,938,000 5,356,000 -3,307,000 3,774,000 -786,000 
          deferred revenue
        -608,000 -2,482,000 -2,250,000 -11,382,000 5,437,000 -4,122,000 -1,537,000 -9,067,000 -1,159,000 -4,124,000 6,173,000 -5,646,000 2,012,000 -3,896,000 7,178,000 -4,298,000 8,554,000 -14,840,000 15,301,000 -13,926,000 15,988,000 -19,321,000 24,122,000 -8,856,000 16,973,000 -11,721,000 8,636,000 -7,455,000 8,858,000 -7,863,000 11,571,000 -4,915,000 5,185,000 -8,466,000 9,449,000 -5,649,000 3,270,000 -15,168,000 15,546,000 -12,448,000 11,798,000 -31,110,000 26,329,000 -25,217,000 20,378,000 -47,871,000 48,287,000 -28,071,000 29,312,000 
          accrued liabilities
        -18,186,000 -56,422,000 -2,188,000 3,781,000 -4,894,000 254,000 50,906,000 -4,697,000 640,000 -1,193,000 991,000 -4,571,000 -2,569,000 3,212,000 -2,289,000 -13,479,000 -7,555,000 -5,353,000 6,355,000 -5,189,000 9,386,000 -11,832,000 16,887,000 1,417,000 15,972,000 -18,301,000 15,698,000 2,181,000 216,000 -12,206,000 18,722,000 1,608,000 -4,286,000 -10,793,000 11,699,000 4,924,000 -3,743,000 -15,496,000 12,939,000 9,818,000 -16,760,000 -5,073,000 15,884,000 2,696,000 -8,270,000 2,622,000 7,629,000 -1,705,000 -1,098,000 
          other liabilities
        -841,000 1,321,000 -1,755,000 -770,000 -752,000 -4,817,000 -88,000 -1,300,000 -1,580,000 -1,527,000 -1,605,000 -1,808,000 -6,397,000 -528,000 -2,275,000 -874,000 -2,091,000 -1,499,000 -1,831,000 -1,080,000 -1,197,000 -1,863,000 -1,142,000 296,000 -1,242,000 -618,000 1,274,000 -919,000 -3,148,000 950,000 335,000 1,116,000 138,000 -1,108,000 265,000 598,000 260,000 281,000 101,000 -28,000 -165,000 -152,000 -583,000 447,000 -58,000 -886,000 116,000 -199,000 71,000 
          net cash from operating activities
        4,105,000 -9,009,000 4,813,000 -4,840,000 24,526,000 18,128,000 39,532,000 14,227,000 53,318,000 77,484,000 32,807,000 62,747,000 73,160,000 74,020,000 37,961,000 63,720,000 80,035,000 65,101,000 63,622,000 70,928,000 73,573,000 67,787,000 46,450,000 59,238,000 62,967,000 26,828,000 38,729,000 29,905,000 17,941,000 30,446,000 21,152,000 16,962,000 6,553,000 21,701,000 13,291,000 15,321,000 835,000 -5,788,000 37,849,000 12,110,000 -19,233,000 -18,196,000 31,173,000 -19,750,000 6,691,000 473,000 45,404,000 -6,544,000 29,142,000 
          capital expenditures
        -1,042,000 -6,472,000 -5,756,000 -7,230,000 -8,665,000 -13,294,000 -15,842,000 -17,800,000 -28,017,000 -25,754,000 -23,434,000 -16,698,000 -17,166,000 -23,850,000 -21,956,000 -27,753,000 -29,533,000 -27,054,000 -20,531,000 -27,611,000 -18,984,000 -23,860,000 -14,346,000 -23,146,000 -19,965,000 -10,806,000 -8,029,000 -9,431,000 -14,060,000 -13,175,000 -7,961,000 -5,204,000 -4,883,000 -6,212,000 -7,423,000 -7,737,000 -4,770,000 -6,855,000 -3,617,000 -9,417,000 -4,800,000 -2,369,000 -1,738,000 -2,660,000 -1,486,000 -1,276,000 -1,311,000 -1,211,000 -1,285,000 
          free cash flows
        3,063,000 -15,481,000 -943,000 -12,070,000 15,861,000 4,834,000 23,690,000 -3,573,000 25,301,000 51,730,000 9,373,000 46,049,000 55,994,000 50,170,000 16,005,000 35,967,000 50,502,000 38,047,000 43,091,000 43,317,000 54,589,000 43,927,000 32,104,000 36,092,000 43,002,000 16,022,000 30,700,000 20,474,000 3,881,000 17,271,000 13,191,000 11,758,000 1,670,000 15,489,000 5,868,000 7,584,000 -3,935,000 -12,643,000 34,232,000 2,693,000 -24,033,000 -20,565,000 29,435,000 -22,410,000 5,205,000 -803,000 44,093,000 -7,755,000 27,857,000 
          cash flows from investing activities
                                                         
          purchases of property and equipment
        -1,042,000 -6,472,000 -5,756,000 -7,230,000 -8,665,000 -13,294,000 -15,842,000 -17,800,000 -28,017,000 -25,754,000 -23,434,000 -16,698,000 -17,166,000 -23,850,000 -21,956,000 -27,753,000 -29,533,000 -27,054,000 -20,531,000 -27,611,000 -18,984,000 -23,860,000 -14,346,000 -23,146,000 -19,965,000 -10,806,000 -8,029,000 -9,431,000 -14,060,000 -13,175,000 -7,961,000 -5,204,000 -4,883,000 -6,212,000 -7,423,000 -7,737,000 -4,770,000 -6,855,000 -3,617,000 -9,417,000 -4,800,000 -2,369,000 -1,738,000 -2,660,000 -1,486,000 -1,276,000 -1,311,000 -1,211,000 -1,285,000 
          purchases of investments
         -793,000 -36,737,000 -10,544,000 -44,641,000 -79,028,000 -52,664,000 -32,866,000 -55,037,000 -497,372,000 -196,501,000 -177,455,000 -83,273,000 -273,280,000 -114,324,000 -589,454,000 -58,858,000 -925,748,000 -77,458,000 -691,073,000 -164,612,000 -112,421,000 -137,042,000 -295,506,000                       
          maturities of investments
        13,477,000 18,931,000 3,414,000 4,496,000 103,214,000 74,764,000 7,017,000 39,159,000 50,731,000 36,000,000 84,335,000 69,103,000 407,759,000 101,028,000 261,446,000 180,407,000 342,059,000 311,472,000 437,779,000 274,221,000 181,315,000 127,843,000 140,335,000 149,927,000 121,784,000 133,956,000 104,639,000                       
          proceeds from sale of investments
        5,679,000 181,158,000     155,852,000                                      
          net cash from investing activities
        18,114,000 12,459,000 -2,342,000 -2,734,000 274,914,000 94,810,000 -19,369,000 -23,282,000 -40,814,000 113,434,000 25,786,000 236,232,000 -106,779,000 342,666,000 56,044,000 69,253,000 -363,072,000 376,769,000 -167,753,000 190,168,000 -764,952,000 18,156,000 -572,460,000 -131,220,000 -47,262,000 -93,041,000 -145,635,000 -477,922,000 13,173,000  -26,915,000 -23,415,000 4,236,000 -25,329,000 -105,341,000 -7,549,000 1,985,000 -6,364,000 3,498,000 -3,136,000 39,000 3,806,000 14,630,000 2,587,000 -12,752,000 2,557,000 -23,073,000 -3,633,000 -63,201,000 
          cash flows from financing activities
                                                         
          payment of taxes related to the net share settlement of equity awards
        -597,000 -958,000 -605,000 -568,000 -469,000 -591,000 -823,000 -3,531,000 -4,294,000 -2,583,000 -2,789,000 -3,332,000 -7,736,000 -13,773,000 -2,555,000 -2,754,000 -7,467,000 -5,084,000 -14,697,000 -15,466,000 -59,176,000 -15,456,000 -11,120,000 -7,268,000 -46,836,000 -3,495,000 -8,825,000 -6,207,000 -76,044,000 -3,420,000 -5,355,000 -4,674,000 -35,640,000                 
          repayment of convertible senior notes
        -19,450,000 -8,356,000 -416,492,000     -136,225,000      -7,000 -4,000 -110,902,000 -189,849,000 -144,290,000                            
          net cash from financing activities
        -20,047,000 -10,737,000 -604,000 -177,000 -416,961,000 -102,685,000 -822,000 -1,341,000 -4,294,000 -149,964,000 -138,987,000 -404,917,000 -158,902,000 -11,854,000 -426,836,000 1,348,000 -307,461,000 -301,577,000 -22,045,000 -77,256,000 867,600,000 -133,818,000 768,510,000 -1,896,000 -44,169,000 3,882,000 1,690,000 89,455,000 508,482,000 2,233,000 75,000 284,528,000 -30,418,000 7,858,000 148,191,000 -11,980,000 -9,855,000 -732,000 -813,000 -799,000 -6,331,000 478,000 51,000 2,222,000 -28,000 -99,000 72,000 1,520,000 -3,365,000 
          effect of exchange rate changes
        -418,000 -96,000 -651,000 273,000 218,000 -876,000 156,000 -79,000 -226,000 400,000 -576,000 10,000 187,000 -491,000 4,628,000                                 
          net increase in cash, cash equivalents and restricted cash
        1,754,000 -7,383,000   -117,303,000    7,984,000     404,341,000 -332,831,000 134,321,000 -585,870,000 140,293,000 -126,176,000 183,840,000 176,221,000 -47,875,000 242,500,000 -73,878,000 -28,464,000 -62,331,000 -105,216,000 -358,562,000 539,596,000 -3,776,000 -5,688,000                   
          cash, cash equivalents and restricted cash, beginning of period
        33,411,000 164,359,000 137,976,000 475,854,000 855,893,000 481,715,000 389,432,000 375,945,000 126,963,000                 
          cash, cash equivalents and restricted cash, end of period
        35,165,000 -7,383,000 1,216,000 -7,478,000 47,056,000 9,377,000 19,497,000 -10,475,000 145,960,000 41,354,000 -80,970,000 -105,928,000 283,520,000 404,341,000 -332,831,000 134,321,000 270,023,000 140,293,000 -126,176,000 183,840,000 657,936,000 -47,875,000 242,500,000 -73,878,000 360,968,000 -62,331,000 -105,216,000 -358,562,000 915,541,000 -3,776,000 -5,688,000 278,075,000 107,334,000                 
          gain on early extinguishments of debt
                                                         
          loss contingency
                                                        
          impairment expense
           195,708,000                                           
          realized loss on sale of investments
                                                         
          impairment of lease related assets
         4,311,000                                               
          impairment of equity investment
                                                         
          proceeds from disposition of textbooks
                   3,500,000 9,000 -5,000 2,499,000 899,000 1,106,000 2,671,000 4,038,000 557,000 3,597,000 1,245,000 2,170,000                         
          proceeds from sale of equity investments
                                                         
          purchases of equity investments
                                                         
          proceeds from common stock issued under stock plans
         198,000 1,000   445,000 1,000   1,057,000 27,000 2,936,000 145,000 1,919,000 4,102,000 456,000 3,514,000 106,000 4,920,000 347,000 6,247,000                            
          proceeds from exercise of convertible senior notes capped call
                       1,000 44,192,000 24,812,000 19,681,000                            
          payment of withholding tax
                                                         
          repurchase of common stock
                                 -20,000,000           -2,263,000     
          net loss
          -17,471,000 -35,663,000 -17,484,000             24,306,000   -65,179,000 26,043,000   -5,713,000 8,219,000 -11,477,000 -2,029,000 -4,318,000 5,347,000 -13,709,000 -3,909,000 -2,617,000 3,659,000 -11,516,000 -6,025,000 -6,401,000 -1,489,000 -16,063,000 -9,008,000 -15,685,000 3,630,000 -24,167,000 -10,131,000 -28,542,000    -25,759,000 
          adjustments to reconcile net loss to net cash from operating activities:
                                                         
          impairment of strategic equity investment
                                                        
          proceeds from sale of strategic equity investment
              15,500,000           236,000 6,845,000                             
          net decrease in cash, cash equivalents and restricted cash
                  -80,970,000 -105,928,000 -192,334,000                    -19,629,000                 
          loss on early extinguishments of debt
                                                         
          loss contingency accrual
                                                         
          gain on textbook library
                             575,000 -657,000 -196,000 -1,175,000                         
          print textbook depreciation expense
                     89,000 1,521,000 1,835,000 2,443,000 2,821,000 3,760,000 4,698,000 3,637,000 3,535,000 3,527,000                         
          gain on foreign currency remeasurement of purchase consideration
                     -4,628,000                                 
          impairment on lease related assets
             3,368,000       1,814,000                                   
          change in assets and liabilities, net of effect of acquisition of business:
                                                         
          purchases of textbooks
                     -123,000 -3,692,000 -265,000 -5,648,000 -491,000 -4,527,000 -8,926,000 -10,973,000 -1,838,000 -36,830,000             -91,000 -244,000 -109,000 -442,000 -71,000 -951,000 -2,133,000 -29,142,000 -13,345,000 -46,688,000 -9,818,000 -42,963,000 
          proceeds from sale of strategic equity investments
                                                        
          acquisition of business, net of cash acquired
                            -7,891,000                 -700,000           
          purchases of strategic equity investments
                                                         
          net increase in cash, cash equivalents and restricted ca
                                                         
          deferred income taxes
              71,000 138,155,000 2,877,000  787,000 16,701,000 3,441,000         -92,000 221,000 73,000 -311,000 -98,000 20,000   -8,000               335,000   
          operating lease expense
              1,506,000 1,574,000 1,567,000  1,526,000                                       
          loss from write-off of property and equipment
              367,000 1,179,000 478,000  3,128,000 330,000 120,000  350,000 2,141,000 626,000  815,000 285,000 757,000  206,000                          
          purchase of strategic equity investment
                  -2,249,000           -2,000,000                       
          other depreciation and amortization expense
                 20,773,000 56,918,000 26,484,000 25,543,000 25,702,000 22,374,000 21,636,000 20,285,000 17,001,000 16,086,000 15,341,000 14,846,000 13,930,000 13,254,000 10,591,000 9,243,000         5,036,000 5,208,000 4,704,000 4,389,000 4,519,000 3,933,000 3,491,000 2,577,000 2,331,000 2,767,000 3,241,000 3,172,000 3,336,000 3,279,000 2,509,000 2,035,000 
          impairment of intangible asset
                                                        
          loss on textbook library
                     -9,000 -4,357,000 -610,000 2,191,000 4,535,000 202,000 4,028,000                             
          gain on sale of strategic equity investments
                                                        
          loss on change in fair value of derivative instruments
                         7,148,000                             
          change in assets and liabilities, net of effect of acquisition of businesses:
                                                         
          acquisition of businesses, net of cash acquired
                     -401,125,000                          -10,000,000   
          proceeds from equity offering, net of offering costs
                         1,091,466,000                             
          payment of escrow related to acquisition
                                                        
          tax benefit related to release of valuation allowance
                                                         
          repurchases of common stock
                  -35,057,000 -151,311,000  -23,078,000 -300,450,000                                 
          restructuring charges
                                                         
          amortization of debt discount and issuance costs
                         1,413,000 1,412,000 1,471,000 1,626,000 21,663,000 17,018,000 12,946,000 12,946,000 13,088,000 13,089,000 13,020,000 4,005,000 3,536,000 3,537,000                   
          repayment of convertible senior notes attributable to debt discount
                             -5,521,000                            
          loss from impairment of strategic equity investment
                                                        
          proceeds from issuance of convertible senior notes, net of issuance costs
                                97,586,000 682,594,000 17,000                   
          purchase of convertible senior notes capped call
                                -12,150,000 -85,050,000                   
          loss on early extinguishment of debt
                          78,152,000                             
          gain on sale of strategic equity investment
                           -5,338,000                             
          operating activities
                                                         
          investing activities
                                                         
          financing activities
                                                         
          purchases of strategic equity investment
                                                         
          common stock issued under stock plans
                               5,372,000 2,667,000 7,377,000 10,515,000 10,226,000 6,982,000 5,653,000 5,413,000 12,828,000 5,222,000 10,094,000 3,800,000 7,002,000 2,763,000 990,000 4,000   1,108,000        
          gain on liquidation of textbooks
                                         -4,766,000 -147,000 2,673,000 -2,191,000 -1,005,000 -1,677,000 -909,000 2,445,000 -4,185,000 1,289,000 -2,044,000 -2,122,000 -1,678,000 
          loss from write-offs of textbooks
                                         314,000 194,000 423,000 249,000 224,000 763,000 923,000 1,067,000 2,544,000    4,402,000 
          interest accretion on deferred consideration
                                                       
          other
                                                         
          change in assets and liabilities net of effect of acquisition of businesses:
                                                         
          proceeds from liquidations of textbooks
                                         6,943,000 1,773,000 9,079,000 8,674,000 6,120,000 4,030,000 11,537,000 10,714,000 11,979,000 17,944,000 21,438,000 7,461,000 11,276,000 
          payment of deferred cash consideration related to acquisitions
                                         -189,000               
          proceeds from follow-on offering, net of offering costs
                                         -23,000                
          supplemental cash flow data:
                                                         
          cash paid during the period for:
                                                         
          interest
                                      18,000 18,000 19,000 19,000 18,000 18,000 30,000 3,000 28,000 19,000 19,000 26,000 25,000 25,000 26,000 57,000 31,000 
          income taxes
                                   286,000 626,000  616,000 441,000 503,000 549,000 420,000 433,000 388,000 263,000 579,000 -150,000 402,000 141,000 115,000 148,000 423,000 107,000 73,000 85,000 360,000 
          cash paid for amounts included in the measurement of lease liabilities:
                                                         
          operating cash flows from operating leases
                                   -3,451,000 1,126,000                     
          non-cash investing activities:
                                                         
          accrued purchases of long-lived assets
                                   43,000 5,127,000  -2,344,000 2,133,000 3,204,000 -139,000 2,568,000 -878,000 2,022,000 816,000 324,000 -1,117,000 2,310,000 772,000 -2,806,000 1,046,000 2,759,000 -1,604,000 1,208,000 2,867,000 2,661,000 
          purchases of marketable securities
                                    -21,572,000 -33,580,000 -46,642,000 -54,123,000 -12,511,000 -15,830,000    -7,633,000 -15,635,000 -2,848,000 -10,884,000 -6,243,000 -6,834,000 -8,990,000 -12,053,000 -42,829,000 
          maturities of marketable securities
                                    48,805,000 20,300,000 46,100,000 50,350,000 21,630,000     600,000 6,244,000 17,851,000 10,299,000 7,550,000 12,140,000 12,470,000 8,630,000   
          textbook library depreciation expense
                                             364,000 1,683,000 2,724,000 4,496,000 6,715,000 9,362,000 12,802,000 14,674,000 15,927,000 16,090,000 18,035,000 20,095,000 
          amortization of warrants and deferred loan costs
                                                   35,000 35,000 35,000 35,000 88,000 29,000 
          proceeds from sale of marketable securities
                                        1,894,000    22,280,000 550,000    3,650,000 3,848,000   
          net cash from by investing activities
                                                         
          non-cash investing and financing activities:
                                                         
          reconciliation of cash, cash equivalents and restricted cash:
                                                         
          cash and cash equivalents
                                      -5,906,000 278,099,000 106,827,000                 
          restricted cash included in other assets
                                      218,000 60,000 423,000                 
          total cash, cash equivalents and restricted cash
                                      -5,688,000 278,075,000 107,334,000                 
          acquisition of business
                                            -188,000            -500,000 
          restricted cash included in other current assets
                                        84,000                 
          provision (release) for bad debts
                                                         
          realized loss on sale of securities
                                                         
          net increase in cash and cash equivalents
                                         4,230,000    -12,884,000    -13,912,000      -8,657,000 -37,424,000 
          cash and cash equivalents, beginning of period
                                         77,329,000 67,029,000 56,117,000 76,864,000 
          cash and cash equivalents, end of period
                                         4,230,000 56,141,000 -4,208,000 70,294,000 -12,884,000 40,534,000 8,175,000 41,504,000 -13,912,000 45,854,000 -14,941,000 50,028,000 2,931,000 22,403,000 -8,657,000 39,440,000 
          issuance of common stock related to prior acquisition
                                                 825,000     
          change in assets and liabilities, net of acquisition of business:
                                                         
          payment of taxes related to the net share settlement of rsus
                                          -3,052,000 -2,232,000 -12,618,000 -1,722,000 -817,000 -1,909,000 -6,331,000 -630,000 -608,000 -3,081,000 -4,391,000 -206,000 -186,000 -134,000 -3,454,000 
          net decrease in cash and cash equivalents
                                           -4,208,000 -7,035,000   8,175,000 -25,525,000   -14,941,000 -6,089,000     
          realized gain on sale of securities
                                                     -3,000   
          loss from disposal of property and equipment
                                                   716,000 202,000     
          impairment of intangible assets
                                                         
          release of cash from escrow
                                                         
          accrued deferred cash consideration related to acquisition
                                             728,000 166,000           
          (release) provision for bad debts
                                                         
          revaluation of preferred stock warrants
                                                         
          proceeds from debt obligations
                                                         
          payments of debt obligations
                                                         
          proceeds from initial public offering, net of issuance costs
                                                         
          conversion of preferred stock warrants to common stock warrants
                                                         
          conversion of preferred stock warrants into common stock
                                                         
          issuance of common stock upon exercise of stock warrants
                                                         
          deemed dividend to preferred stockholders
                                                         
          issuance of common stock warrants in connection with consulting services
                                                         
          common stock offering costs not yet paid
                                                         
          provision for bad debts
                                                   -45,000 -224,000     
          proceeds from issuance of common stock under employee stock plans
                                                      258,000   
          proceeds from exercise of common stock under employee stock plans
                                                   3,904,000 6,626,000     
          change in assets and liabilities net of effect of acquisition of business:
                                                         
          benefit from bad debts
                                                         
          income from write-offs of textbooks
                                                         
          income from disposal of property and equipment
                                                         
          impairment of intangibles
                                                         
          proceeds from issuance of convertible preferred stock
                                                         
          proceeds from exercise of common stock under employee stock plans and preferred stock warrants
                                                         
          repurchase of common stock and vested stock options
                                                         
          issuance of preferred stock warrants
                                                         
          issuance of common stock related to acquisition
                                                     1,000,000   
          cancellation of common shares held in escrow from acquisitions
                                                         
          stock-based compensation expense
                                                      11,794,000 8,481,000 6,930,000 
          provision for (recovery of) bad debts
                                                        -41,000 
          proceeds from maturities of marketable securities
                                                        13,100,000 
          proceeds from exercise of stock options
                                                        89,000 
          loss from liquidation of textbooks
                                                         
          changes in assets and liabilities:
                                                         
          proceeds from liquidation of textbooks
                                                         
          purchases of property and equipment and other assets
                                                         
          acquisitions of businesses, net of cash acquired
                                                         
          proceeds from exercise of stock options and preferred stock warrants
                                                         
          payment of taxes related to the net settlement of rsus
                                                         
          cash and cash equivalents at beginning of period
                                                         
          cash and cash equivalents at end of period
                                                         
          supplemental cash flow data
                                                         
          conversion of preferred stock into common stock
                                                         
          issuance of common stock and stock options in connection with acquisitions