CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands | Common stock | Additional Paid-in Capital | Accumulated Other Comprehensive Income | Accumulated Deficit | Total |
Beginning balance at Dec. 31, 2018 | $ 34 | $ 430,824 | | $ (184,602) | $ 246,256 |
Beginning balance (in shares) at Dec. 31, 2018 | 34,410,725 | | | | |
Increase (Decrease) in Stockholders' Equity | | | | | |
Stock compensation expense | | 2,644 | | | 2,644 |
Issuance of common stock in connection with ESPP | | 295 | | | 295 |
Issuance of common stock in connection with ESPP (in shares) | 12,105 | | | | |
Issuance of common stock in connection with exercise of stock options | | 54 | | | 54 |
Issuance of common stock in connection with exercise of stock options (in shares) | 7,811 | | | | |
Unrealized gain (loss) on marketable securities | | 214 | | | 214 |
Net loss | | | | (28,974) | (28,974) |
Ending balance at Mar. 31, 2019 | $ 34 | 434,031 | | (213,576) | 220,489 |
Ending balance (in shares) at Mar. 31, 2019 | 34,430,641 | | | | |
Beginning balance at Dec. 31, 2018 | $ 34 | 430,824 | | (184,602) | 246,256 |
Beginning balance (in shares) at Dec. 31, 2018 | 34,410,725 | | | | |
Increase (Decrease) in Stockholders' Equity | | | | | |
Net loss | | | | | (107,773) |
Ending balance at Sep. 30, 2019 | $ 35 | 441,455 | | (292,375) | 149,115 |
Ending balance (in shares) at Sep. 30, 2019 | 34,578,564 | | | | |
Beginning balance at Mar. 31, 2019 | $ 34 | 434,031 | | (213,576) | 220,489 |
Beginning balance (in shares) at Mar. 31, 2019 | 34,430,641 | | | | |
Increase (Decrease) in Stockholders' Equity | | | | | |
Stock compensation expense | | 3,272 | | | 3,272 |
Issuance of common stock in connection with exercise of stock options | | 465 | | | 465 |
Issuance of common stock in connection with exercise of stock options (in shares) | 66,901 | | | | |
Change in unrealized gain (loss) on marketable securities | | 37 | | | 37 |
Net loss | | | | (42,796) | (42,796) |
Ending balance at Jun. 30, 2019 | $ 34 | 437,805 | | (256,372) | 181,467 |
Ending balance (in shares) at Jun. 30, 2019 | 34,497,542 | | | | |
Increase (Decrease) in Stockholders' Equity | | | | | |
Stock compensation expense | | 3,035 | | | 3,035 |
Issuance of common stock in connection with ESPP | | 263 | | | 263 |
Issuance of common stock in connection with ESPP (in shares) | 13,766 | | | | |
Issuance of common stock in connection with exercise of stock options | $ 1 | 433 | | | 434 |
Issuance of common stock in connection with exercise of stock options (in shares) | 67,256 | | | | |
Unrealized gain (loss) on marketable securities | | (81) | | | (81) |
Net loss | | | | (36,003) | (36,003) |
Ending balance at Sep. 30, 2019 | $ 35 | 441,455 | | (292,375) | 149,115 |
Ending balance (in shares) at Sep. 30, 2019 | 34,578,564 | | | | |
Beginning balance at Dec. 31, 2019 | | | | | |
Beginning balance at Dec. 31, 2019 | $ 44 | 606,307 | | (325,331) | 281,020 |
Beginning balance (in shares) at Dec. 31, 2019 | 43,996,753 | | | | |
Increase (Decrease) in Stockholders' Equity | | | | | |
Stock compensation expense | | 5,475 | | | 5,475 |
Issuance of common stock in connection with ESPP | | 324 | | | 324 |
Issuance of common stock in connection with ESPP (in shares) | 18,673 | | | | |
Issuance of common stock in connection with exercise of stock options | | 383 | | | 383 |
Issuance of common stock in connection with exercise of stock options (in shares) | 72,964 | | | | |
Unrealized gain (loss) on marketable securities | | | $ 63 | | 63 |
Net loss | | | | (34,164) | (34,164) |
Ending balance at Mar. 31, 2020 | $ 44 | 612,489 | 63 | (359,495) | 253,101 |
Ending balance (in shares) at Mar. 31, 2020 | 44,088,390 | | | | |
Beginning balance at Dec. 31, 2019 | | | | | |
Ending balance at Sep. 30, 2020 | | | | | |
Beginning balance at Dec. 31, 2019 | $ 44 | 606,307 | | (325,331) | 281,020 |
Beginning balance (in shares) at Dec. 31, 2019 | 43,996,753 | | | | |
Increase (Decrease) in Stockholders' Equity | | | | | |
Net loss | | | | | (99,099) |
Ending balance at Sep. 30, 2020 | $ 44 | 621,085 | 238 | (424,430) | 196,937 |
Ending balance (in shares) at Sep. 30, 2020 | 44,204,745 | | | | |
Beginning balance at Mar. 31, 2020 | $ 44 | 612,489 | 63 | (359,495) | 253,101 |
Beginning balance (in shares) at Mar. 31, 2020 | 44,088,390 | | | | |
Increase (Decrease) in Stockholders' Equity | | | | | |
Stock compensation expense | | 3,028 | | | 3,028 |
Issuance of common stock in connection with exercise of stock options | | 174 | | | 174 |
Issuance of common stock in connection with exercise of stock options (in shares) | 27,222 | | | | |
Change in unrealized gain (loss) on marketable securities | | | 567 | | 567 |
Net loss | | | | (31,117) | (31,117) |
Ending balance at Jun. 30, 2020 | $ 44 | 615,691 | 630 | (390,612) | 225,753 |
Ending balance (in shares) at Jun. 30, 2020 | 44,115,612 | | | | |
Ending balance at Sep. 30, 2020 | | | | | |
Increase (Decrease) in Stockholders' Equity | | | | | |
Stock compensation expense | | 4,695 | | | 4,695 |
Issuance of common stock in connection with ESPP | | 198 | | | 198 |
Issuance of common stock in connection with ESPP (in shares) | 11,379 | | | | |
Issuance of common stock in connection with exercise of stock options and vesting of restricted stock units | | 501 | | | 501 |
Issuance of common stock in connection with exercise of stock options and vesting of restricted stock units (in shares) | 77,754 | | | | |
Unrealized gain (loss) on marketable securities | | | (392) | | (392) |
Net loss | | | | (33,818) | (33,818) |
Ending balance at Sep. 30, 2020 | $ 44 | $ 621,085 | $ 238 | $ (424,430) | $ 196,937 |
Ending balance (in shares) at Sep. 30, 2020 | 44,204,745 | | | | |