v3.20.2
Stockholders' Equity (Tables)
 6 Months Ended
Jun. 30, 2020
Stockholders' Equity Note [Abstract]  
Schedule of shares of common stock reserved for future issuance As of June 30, 2020, there were 64,300,599 shares of common stock outstanding, and the Company had reserved a total of 26,638,801 of its authorized shares of common stock for future issuance as follows:
Shares Reserved for Future Issuance
Outstanding restricted stock units3,534,193  
Outstanding performance restricted stock units1,831,648  
Outstanding stock options4,132,718  
Reserved for convertible senior notes17,140,242  
Total shares of common stock reserved for future issuance26,638,801  
Schedule of stock-based compensation expense included in the consolidated statements of operations and comprehensive loss The following table presents stock-based compensation expense related to the Stock Plans and the ESPP, contained on the following line items on the Company’s condensed consolidated statements of operations and comprehensive loss for each of the periods indicated.
 Three Months Ended
June 30,		Six Months Ended
June 30,
 2020201920202019
 (in thousands)
Curriculum and teaching$58  $5  $191  $8  
Servicing and support3,642  1,834  7,570  3,503  
Technology and content development2,936  1,648  6,105  3,504  
Marketing and sales1,853  1,487  5,086  2,743  
General and administrative12,602  4,993  23,009  9,793  
Total stock-based compensation expense$21,091  $9,967  $41,961  $19,551  
Schedule of restricted and performance restricted stock unit activity The following table presents a summary of the Company’s RSU activity for the period indicated.
 Number of
Units		Weighted-
Average Grant
Date Fair Value per Share
Outstanding balance as of December 31, 20192,281,142  $40.49  
Granted1,865,348  20.11  
Vested(476,317) 52.61  
Forfeited(135,980) 32.13  
Outstanding balance as of June 30, 20203,534,193  $28.42  
The following table presents a summary of the Company’s PRSU activity for the period indicated.
 Number of
Units		Weighted-
Average Grant
Date Fair Value per Share
Outstanding balance as of December 31, 20191,413,773  $28.12  
Granted653,879  22.46  
Vested(444) 64.51  
Forfeited(235,560) 52.91  
Outstanding balance as of June 30, 20201,831,648  $22.90  
Schedule of stock option activity The following table presents a summary of the Company’s stock option activity for the period indicated.
 Number of
Options		Weighted-Average
Exercise Price per
Share		Weighted-Average Remaining Contractual Term (in years)Aggregate
Intrinsic
Value
(in thousands)
Outstanding balance as of December 31, 20194,373,895  $34.24  5.88$28,736  
Granted8,597  19.61  
Exercised(195,728) 9.32  
Forfeited(22,294) 57.38  
Expired(31,752) 41.11  
Outstanding balance as of June 30, 20204,132,718  35.22  5.5458,683  
Exercisable as of June 30, 20203,162,499  $25.87  4.72$57,663