CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands | Total | Common Stock (Class A and B) | Additional Paid-in-Capital | Accumulated Other Comprehensive Income | Accumulated Deficit |
Shares, Outstanding, Beginning at Dec. 31, 2018 | | 44,044,000 | | | |
Beginning of the period at Dec. 31, 2018 | $ (9,740) | $ 44 | $ 297,145 | $ 98 | $ (307,027) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | |
Stock-based compensation expense | 8,193 | | 8,193 | | |
Issuance of common stock upon exercise of stock options (in shares) | | 961,000 | | | |
Issuance of common stock upon exercise of stock options | 11,055 | $ 1 | 11,054 | | |
Issuance of common stock under employee stock purchase plan (in shares) | | 101,000 | | | |
Issuance of common stock under employee stock purchase plan | 2,149 | | 2,149 | | |
Issuance of restricted stock units (in shares) | | 25,000 | | | |
Tax withholding related to net share settlements of stock-based compensation awards (in shares) | | (10,000) | | | |
Tax withholding related to net share settlements of stock-based compensation awards | (390) | | (390) | | |
Net loss | (7,463) | | | | (7,463) |
Other comprehensive income (loss) | 52 | | | 52 | |
End of period at Mar. 31, 2019 | 3,856 | $ 45 | 318,151 | 150 | (314,490) |
Shares, Outstanding, Ending at Mar. 31, 2019 | | 45,121,000 | | | |
Shares, Outstanding, Beginning at Dec. 31, 2018 | | 44,044,000 | | | |
Beginning of the period at Dec. 31, 2018 | (9,740) | $ 44 | 297,145 | 98 | (307,027) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | |
Net loss | (31,836) | | | | |
Other comprehensive income (loss) | 196 | | | | |
End of period at Sep. 30, 2019 | 70,134 | $ 47 | 408,656 | 294 | (338,863) |
Shares, Outstanding, Ending at Sep. 30, 2019 | | 46,422,000 | | | |
Shares, Outstanding, Beginning at Mar. 31, 2019 | | 45,121,000 | | | |
Beginning of the period at Mar. 31, 2019 | 3,856 | $ 45 | 318,151 | 150 | (314,490) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | |
Stock-based compensation expense | 8,513 | | 8,513 | | |
Issuance of common stock upon exercise of stock options (in shares) | | 455,000 | | | |
Issuance of common stock upon exercise of stock options | 5,498 | $ 1 | 5,497 | | |
Issuance of restricted stock units (in shares) | | 323,000 | | | |
Net loss | (8,322) | | | | (8,322) |
Other comprehensive income (loss) | 82 | | | 82 | |
End of period at Jun. 30, 2019 | 9,627 | $ 46 | 332,161 | 232 | (322,812) |
Shares, Outstanding, Ending at Jun. 30, 2019 | | 45,899,000 | | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | |
Stock-based compensation expense | 9,223 | | 9,223 | | |
Issuance of common stock upon exercise of stock options (in shares) | | 401,000 | | | |
Issuance of common stock upon exercise of stock options | 5,940 | $ 1 | 5,939 | | |
Issuance of common stock under employee stock purchase plan (in shares) | | 87,000 | | | |
Issuance of common stock under employee stock purchase plan | 2,773 | | 2,773 | | |
Issuance of restricted stock units (in shares) | | 35,000 | | | |
Equity component of convertible senior notes, net | 58,560 | | 58,560 | | |
Net loss | (16,051) | | | | (16,051) |
Other comprehensive income (loss) | 62 | | | 62 | |
End of period at Sep. 30, 2019 | 70,134 | $ 47 | 408,656 | 294 | (338,863) |
Shares, Outstanding, Ending at Sep. 30, 2019 | | 46,422,000 | | | |
Shares, Outstanding, Beginning at Dec. 31, 2019 | | 46,639,000 | | | |
Beginning of the period at Dec. 31, 2019 | 65,343 | $ 47 | 420,170 | 287 | (355,161) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | |
Stock-based compensation expense | 9,936 | | 9,936 | | |
Issuance of common stock upon exercise of stock options (in shares) | | 225,000 | | | |
Issuance of common stock upon exercise of stock options | 2,794 | | 2,794 | | |
Issuance of common stock under employee stock purchase plan (in shares) | | 94,000 | | | |
Issuance of common stock under employee stock purchase plan | 3,660 | | 3,660 | | |
Issuance of restricted stock units (in shares) | | 117,000 | | | |
Tax withholding related to net share settlements of stock-based compensation awards (in shares) | | (30,000) | | | |
Tax withholding related to net share settlements of stock-based compensation awards | (1,379) | | (1,379) | | |
Net loss | (10,573) | | | | (10,573) |
Other comprehensive income (loss) | (9) | | | (9) | |
End of period at Mar. 31, 2020 | 69,772 | $ 47 | 435,181 | 278 | (365,734) |
Shares, Outstanding, Ending at Mar. 31, 2020 | | 47,045,000 | | | |
Shares, Outstanding, Beginning at Dec. 31, 2019 | | 46,639,000 | | | |
Beginning of the period at Dec. 31, 2019 | $ 65,343 | $ 47 | 420,170 | 287 | (355,161) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | |
Issuance of common stock upon exercise of stock options (in shares) | 1,038,807 | | | | |
Net loss | $ (40,845) | | | | |
Other comprehensive income (loss) | 200 | | | | |
End of period at Sep. 30, 2020 | 79,498 | $ 48 | 474,969 | 487 | (396,006) |
Shares, Outstanding, Ending at Sep. 30, 2020 | | 48,131,000 | | | |
Shares, Outstanding, Beginning at Mar. 31, 2020 | | 47,045,000 | | | |
Beginning of the period at Mar. 31, 2020 | 69,772 | $ 47 | 435,181 | 278 | (365,734) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | |
Stock-based compensation expense | 14,894 | | 14,894 | | |
Issuance of common stock upon exercise of stock options (in shares) | | 443,000 | | | |
Issuance of common stock upon exercise of stock options | 6,664 | $ 0 | 6,664 | | |
Issuance of restricted stock units (in shares) | | 153,000 | | | |
Tax withholding related to net share settlements of stock-based compensation awards (in shares) | | (21,000) | | | |
Tax withholding related to net share settlements of stock-based compensation awards | (732) | | (732) | | |
Net loss | (19,765) | | | | (19,765) |
Other comprehensive income (loss) | 390 | | | 390 | |
End of period at Jun. 30, 2020 | 71,223 | $ 47 | 456,007 | 668 | (385,499) |
Shares, Outstanding, Ending at Jun. 30, 2020 | | 47,620,000 | | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | |
Stock-based compensation expense | 10,601 | | 10,601 | | |
Issuance of common stock upon exercise of stock options (in shares) | | 371,000 | | | |
Issuance of common stock upon exercise of stock options | 4,795 | $ 1 | 4,794 | | |
Issuance of common stock under employee stock purchase plan (in shares) | | 93,000 | | | |
Issuance of common stock under employee stock purchase plan | 3,567 | | 3,567 | | |
Issuance of restricted stock units (in shares) | | 47,000 | | | |
Net loss | (10,507) | | | | (10,507) |
Other comprehensive income (loss) | (181) | | | (181) | |
End of period at Sep. 30, 2020 | $ 79,498 | $ 48 | $ 474,969 | $ 487 | $ (396,006) |
Shares, Outstanding, Ending at Sep. 30, 2020 | | 48,131,000 | | | |