v3.10.0.1

Stock-Based Compensation (Tables) | 9 Months Ended
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Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |
Schedule of stock-based compensation expense included in the consolidated statements of operations and comprehensive loss | Stock-based compensation expense related to stock-based awards, as well as the ESPP, is included in the following line items in the condensed consolidated statements of operations and comprehensive loss:
| Three Months Ended September 30, |  | Nine Months Ended September 30,
| 2018 |  | 2017 |  | 2018 |  | 2017
| (in thousands)
Curriculum and teaching | $ | 3 |  |  | $ | 2 |  |  | $ | 10 |  |  | $ | 2 |
Servicing and support | 1,346 |  |  | 1,100 |  |  | 3,538 |  |  | 2,956 |
Technology and content development | 1,089 |  |  | 904 |  |  | 2,875 |  |  | 2,447 |
Marketing and sales | 839 |  |  | 463 |  |  | 2,046 |  |  | 1,235 |
General and administrative | 4,656 |  |  | 3,678 |  |  | 15,595 |  |  | 8,897 |
Total stock-based compensation expense | $ | 7,933 |  |  | $ | 6,147 |  |  | $ | 24,064 |  |  | $ | 15,537 |
Schedule of stock option activity | The following is a summary of the stock option activity for the nine months ended September 30, 2018:
| Number of Options |  | Weighted-Average Exercise Price per Share
Outstanding balance at December 31, 2017 | 4,559,176 |  |  | $ | 15.10 |
Granted | 663,615 |  |  | 84.13 |
Exercised | (1,000,574 | ) |  | 7.03 |
Forfeited | (124,737 | ) |  | 41.20 |
Expired | — |  |  | — |
Outstanding balance at September 30, 2018 | 4,097,480 |  |  | 27.45 |
Exercisable at September 30, 2018* | 2,814,863 |  |  | 13.34 |
* | As of September 30, 2018, the aggregate intrinsic value of options exercisable was $174.2 million and such shares had a weighted-average remaining contractual term of 5.08 years.
Schedule of restricted stock unit activity | The following is a summary of restricted stock unit activity for the nine months ended September 30, 2018:
| Number of Restricted Stock Units |  | Weighted- Average Grant Date Fair Value
Outstanding balance at December 31, 2017 | 1,413,423 |  |  | $ | 29.95 |
Granted | 523,281 |  |  | 81.74 |
Vested | (585,799 | ) |  | 25.54 |
Forfeited | (133,744 | ) |  | 43.98 |
Outstanding balance at September 30, 2018 | 1,217,161 |  |  | 52.80 |

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- Definition Tabular disclosure of the allocation of equity-based compensation costs to a given line item on the balance sheet and income statement for the period. This may include the reporting line for the costs and the amount capitalized and expensed. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5047-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 + Details
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- Definition Tabular disclosure of the number and weighted-average grant date fair value for restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock units that were granted, vested, or forfeited during the year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Tabular disclosure for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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