v3.8.0.1

Stock-Based Compensation - Expense (Details) $ / shares in Units, $ in Thousands |  | 12 Months Ended |  |
--- | --- | --- | --- | ---
Jan. 01, 2018 $ / shares shares | Dec. 31, 2017 USD ($) item $ / shares shares | Dec. 31, 2016 USD ($) $ / shares shares | Dec. 31, 2015 USD ($) | Jan. 01, 2017 shares | Jan. 30, 2014 shares
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Number of share-based employee compensation plans | item |  | 2 |  |  |  |
Common stock reserved for issuance |  | 11,388,192 |  |  |  |
Stock-based compensation expense | $ |  | $ 21,930 | $ 15,823 | $ 12,499 |  |
Curriculum and teaching |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Stock-based compensation expense | $ |  | 3 |  |  |  |
Servicing and support |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Stock-based compensation expense | $ |  | 4,036 | 3,245 | 2,270 |  |
Technology and content development |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Stock-based compensation expense | $ |  | 3,306 | 2,392 | 1,548 |  |
Marketing and sales |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Stock-based compensation expense | $ |  | 1,742 | 1,317 | 1,057 |  |
General and administrative |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Stock-based compensation expense | $ |  | $ 12,843 | $ 8,869 | $ 7,624 |  |
Restricted Stock Units |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Restricted stock units outstanding |  | 1,413,423 | 1,412,934 |  |  |
Number of restricted stock units granted (in shares) |  | 620,259 |  |  |  |
Stock options |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Option to purchase common stock, outstanding |  | 4,559,176 | 4,882,237 |  |  |
Weighted average exercise price | $ / shares |  | $ 15.10 | $ 10.74 |  |  |
Granted (in shares) |  | 605,640 |  |  |  |
Exercise price (in dollars per share) | $ / shares |  | $ 40.90 |  |  |  |
2008 Equity Incentive Plan |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Number of options or stock awards available for grant under the Plan |  |  |  |  |  | 0
Option to purchase common stock, outstanding |  | 2,146,864 |  |  |  |
Weighted average exercise price | $ / shares |  | $ 4.22 |  |  |  |
Equity Incentive Plan 2014 |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Shares authorized under the plan |  | 2,800,000 |  |  |  |
Number of shares that may be added to the 2014 Plan |  | 5,943,348 |  |  |  |
Period of annual automatic increase in the number of shares authorized |  | 10 years |  |  |  |
Percentage applied on total number of shares of common stock outstanding on previous calendar year for automatic inclusion in the plan |  | 5.00% |  |  |  |
Common stock reserved for issuance | 2,625,292 | 4,415,593 |  |  | 2,357,579 |
Option to purchase common stock, outstanding |  | 2,412,307 |  |  |  |
Weighted average exercise price | $ / shares |  | $ 24.77 |  |  |  |
Equity Incentive Plan 2014 | Maximum |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Number of options or stock awards available for grant under the Plan |  | 5,943,348 |  |  |  |
Equity Incentive Plan 2014 | Restricted Stock Units |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Restricted stock units outstanding |  | 1,413,423 |  |  |  |
Number of restricted stock units granted (in shares) | 7,609 |  |  |  |  |
Equity Incentive Plan 2014 | Stock options |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Granted (in shares) | 8,731 |  |  |  |  |
Exercise price (in dollars per share) | $ / shares | $ 64.51 |  |  |  |  |
Equity Incentive Plan 2014 | Performance Stock Awards |  |  |  |  |  |
Stock-based compensation expense included in the unaudited condensed consolidated statements of operations |  |  |  |  |  |
Number of restricted stock units granted (in shares) | 56,575 |  |  |  |  |

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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: 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 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 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + 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 (a)(3) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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