Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 |
Sep. 30, 2019 |
Jun. 30, 2019 |
Mar. 31, 2019 |
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
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| Quarterly Financial Information Disclosure [Abstract] | |||||||||||
| Revenue | $ 163,178 | $ 153,798 | $ 135,461 | $ 122,234 | $ 115,095 | $ 106,963 | $ 97,423 | $ 92,288 | $ 574,671 | $ 411,769 | $ 286,752 |
| Costs and expenses | |||||||||||
| Curriculum and teaching | 21,925 | 21,336 | 13,308 | 6,701 | 6,625 | 6,351 | 6,007 | 4,307 | 63,270 | 23,290 | 6,609 |
| Servicing and support | 27,372 | 27,351 | 23,993 | 20,174 | 18,087 | 16,586 | 17,297 | 15,233 | 98,890 | 67,203 | 50,767 |
| Technology and content development | 35,504 | 34,132 | 26,043 | 19,794 | 18,376 | 16,361 | 15,235 | 13,840 | 115,473 | 63,812 | 45,926 |
| Marketing and sales | 82,164 | 93,521 | 89,749 | 76,961 | 49,033 | 60,548 | 58,376 | 53,058 | 342,395 | 221,015 | 150,923 |
| General and administrative | 37,549 | 42,040 | 28,408 | 23,023 | 19,666 | 18,974 | 22,480 | 21,869 | 131,020 | 82,989 | 62,665 |
| Impairment charge | 0 | 70,379 | 0 | 0 | 70,379 | 0 | 0 | ||||
| Total costs and expenses | 204,514 | 288,759 | 181,501 | 146,653 | 111,787 | 118,820 | 119,395 | 108,307 | 821,427 | 458,309 | 316,890 |
| Loss from operations | (41,336) | (134,961) | (46,040) | (24,419) | 3,308 | (11,857) | (21,972) | (16,019) | (246,756) | (46,540) | (30,138) |
| Interest income | 713 | 924 | 1,814 | 2,349 | 2,120 | 1,799 | 912 | 342 | 5,800 | 5,173 | 371 |
| Interest expense | (5,289) | (5,651) | (2,424) | (55) | (27) | (27) | (27) | (27) | (13,419) | (108) | (87) |
| Other expense, net | 386 | (710) | (13) | (370) | (229) | (273) | (825) | (395) | (707) | (1,722) | (866) |
| Loss before income taxes | (45,526) | (140,398) | (46,663) | (22,495) | 5,172 | (10,358) | (21,912) | (16,099) | (255,082) | (43,197) | (30,720) |
| Income tax benefit (expense) | 942 | (714) | 18,691 | 941 | (340) | 414 | 3,565 | 1,228 | 19,860 | 4,867 | 1,297 |
| Net loss | $ (44,584) | $ (141,112) | $ (27,972) | $ (21,554) | $ 4,832 | $ (9,944) | $ (18,347) | $ (14,871) | $ (235,222) | $ (38,330) | $ (29,423) |
| Net income (loss) per share, basic (in dollars per share) | $ (0.70) | $ (2.23) | $ (0.46) | $ (0.37) | $ 0.08 | $ (0.17) | $ (0.33) | $ (0.28) | |||
| Net income (loss) per share, diluted (in dollars per share) | $ 0.08 | $ (0.17) | $ (0.33) | $ (0.28) | |||||||
| Weighted-average shares used in computing net income (loss) per share, basic (in shares) | 63,481,130 | 63,358,890 | 60,516,662 | 58,138,692 | 57,924,666 | 57,663,361 | 54,981,192 | 52,687,299 | |||
| Weighted-average shares used in computing net income (loss) per share, diluted (in shares) | 60,666,682 | 57,663,361 | 54,981,192 | 52,687,299 | |||||||
| X | ||||||||||
- Definition Represents cost of service for curriculum and teaching related costs. No definition available.
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| X | ||||||||||
- Definition Represents the amount of servicing and support costs consisting primarily of compensation costs related to program management and operations, as well as costs for platform technical support and faculty and student support. No definition available.
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- Definition Represents cost of service for Technology and content development related costs. No definition available.
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| X | ||||||||||
- Definition Total costs of sales and operating expenses for the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- References No definition available.
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| X | ||||||||||
- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of the cost of borrowed funds accounted for as interest expense. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition The net result for the period of deducting operating expenses from operating revenues. No definition available.
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| X | ||||||||||
- Definition The net amount of other operating income and expenses, the components of which are not separately disclosed on the income statement, from items that are associated with the entity's normal revenue producing operations. No definition available.
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- References No definition available.
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| X | ||||||||||
- Definition Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition The aggregate total amount of expenses directly related to the marketing or selling of products or services. No definition available.
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- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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