Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands | Common Stock | Additional Paid-In Capital | Accumulated Other Comprehensive (Loss) Income | Other Accumulated DeficitCumulative effect adjustment for adoption of new accounting guidance | Other Accumulated Deficit | Cumulative effect adjustment for adoption of new accounting guidance | Total |
Balance, beginning of period at Dec. 31, 2018 | $ 5 | $ 652,464 | $ (29) | $ 803 | $ (416,278) | $ 803 | $ 236,162 |
Balance, beginning of period (in shares) at Dec. 31, 2018 | 48,758,951 | | | | | | |
Statement of Stockholders' Equity (Deficit) | | | | | | | |
Exercise of stock options | | 1,533 | | | | | 1,533 |
Exercise of stock options (in shares) | 146,171 | | | | | | |
Stock-based compensation expense | | 7,855 | | | | | 7,855 |
Vesting of restricted common stock awards (in shares) | 18,000 | | | | | | |
Unrealized gain (loss) on marketable debt securities | | | 58 | | | | 58 |
Net income (loss) | | | | | (29,249) | | (29,249) |
Balance, end of period at Mar. 31, 2019 | $ 5 | 661,852 | 29 | | (444,724) | | 217,162 |
Balance, end of period (in shares) at Mar. 31, 2019 | 48,923,122 | | | | | | |
Balance, beginning of period at Dec. 31, 2018 | $ 5 | 652,464 | (29) | $ 803 | (416,278) | $ 803 | 236,162 |
Balance, beginning of period (in shares) at Dec. 31, 2018 | 48,758,951 | | | | | | |
Statement of Stockholders' Equity (Deficit) | | | | | | | |
Net income (loss) | | | | | | | (95,976) |
Balance, end of period at Sep. 30, 2019 | $ 5 | 721,397 | 39 | | (511,451) | | 209,990 |
Balance, end of period (in shares) at Sep. 30, 2019 | 51,076,198 | | | | | | |
Balance, beginning of period at Mar. 31, 2019 | $ 5 | 661,852 | 29 | | (444,724) | | 217,162 |
Balance, beginning of period (in shares) at Mar. 31, 2019 | 48,923,122 | | | | | | |
Statement of Stockholders' Equity (Deficit) | | | | | | | |
Exercise of stock options | | 2,894 | | | | | 2,894 |
Exercise of stock options (in shares) | 277,259 | | | | | | |
Stock-based compensation expense | | 6,083 | | | | | 6,083 |
Vesting of restricted common stock awards | | 410 | | | | | 410 |
Vesting of restricted common stock awards (in shares) | 24,486 | | | | | | |
Purchase of common stock under benefit plans | | 283 | | | | | 283 |
Purchase of common stock under benefit plans (in shares) | 16,226 | | | | | | |
Unrealized gain (loss) on marketable debt securities | | | 16 | | | | 16 |
Net income (loss) | | | | | (33,786) | | (33,786) |
Balance, end of period at Jun. 30, 2019 | $ 5 | 671,522 | 45 | | (478,510) | | 193,062 |
Balance, end of period (in shares) at Jun. 30, 2019 | 49,241,093 | | | | | | |
Statement of Stockholders' Equity (Deficit) | | | | | | | |
Exercise of stock options | | 1,329 | | | | | 1,329 |
Exercise of stock options (in shares) | 78,804 | | | | | | |
Stock-based compensation expense | | 6,559 | | | | | 6,559 |
Vesting of restricted common stock awards (in shares) | 34,566 | | | | | | |
Issuance of common stock for public offering | | 41,987 | | | | | 41,987 |
Issuance of common stock for public offering (in shares) | 1,721,735 | | | | | | |
Unrealized gain (loss) on marketable debt securities | | | (6) | | | | (6) |
Net income (loss) | | | | | (32,941) | | (32,941) |
Balance, end of period at Sep. 30, 2019 | $ 5 | 721,397 | 39 | | (511,451) | | 209,990 |
Balance, end of period (in shares) at Sep. 30, 2019 | 51,076,198 | | | | | | |
Balance, beginning of period at Dec. 31, 2019 | $ 5 | 811,546 | 107 | | (549,221) | | 262,437 |
Balance, beginning of period (in shares) at Dec. 31, 2019 | 54,355,798 | | | | | | |
Statement of Stockholders' Equity (Deficit) | | | | | | | |
Exercise of stock options | | 3,047 | | | | | 3,047 |
Exercise of stock options (in shares) | 233,208 | | | | | | |
Stock-based compensation expense | | 6,220 | | | | | 6,220 |
Vesting of restricted common stock awards (in shares) | 213,393 | | | | | | |
Unrealized gain (loss) on marketable debt securities | | | 587 | | | | 587 |
Net income (loss) | | | | | (37,724) | | (37,724) |
Balance, end of period at Mar. 31, 2020 | $ 5 | 820,813 | 694 | | (586,945) | | 234,567 |
Balance, end of period (in shares) at Mar. 31, 2020 | 54,802,399 | | | | | | |
Balance, beginning of period at Dec. 31, 2019 | $ 5 | 811,546 | 107 | | (549,221) | | 262,437 |
Balance, beginning of period (in shares) at Dec. 31, 2019 | 54,355,798 | | | | | | |
Statement of Stockholders' Equity (Deficit) | | | | | | | |
Net income (loss) | | | | | | | (53,477) |
Balance, end of period at Sep. 30, 2020 | $ 6 | 1,043,892 | (48) | | (602,698) | | 441,152 |
Balance, end of period (in shares) at Sep. 30, 2020 | 62,187,700 | | | | | | |
Balance, beginning of period at Mar. 31, 2020 | $ 5 | 820,813 | 694 | | (586,945) | | 234,567 |
Balance, beginning of period (in shares) at Mar. 31, 2020 | 54,802,399 | | | | | | |
Statement of Stockholders' Equity (Deficit) | | | | | | | |
Exercise of stock options | | 6,839 | | | | | 6,839 |
Exercise of stock options (in shares) | 355,812 | | | | | | |
Stock-based compensation expense | | 5,417 | | | | | 5,417 |
Vesting of restricted common stock awards (in shares) | 30,194 | | | | | | |
Issuance of common stock for public offering | $ 1 | 203,681 | | | | | 203,682 |
Issuance of common stock for public offering (in shares) | 6,900,000 | | | | | | |
Purchase of common stock under benefit plans | | 350 | | | | | 350 |
Purchase of common stock under benefit plans (in shares) | 15,244 | | | | | | |
Unrealized gain (loss) on marketable debt securities | | | (511) | | | | (511) |
Net income (loss) | | | | | (23,572) | | (23,572) |
Balance, end of period at Jun. 30, 2020 | $ 6 | 1,037,100 | 183 | | (610,517) | | 426,772 |
Balance, end of period (in shares) at Jun. 30, 2020 | 62,103,649 | | | | | | |
Statement of Stockholders' Equity (Deficit) | | | | | | | |
Exercise of stock options | | 947 | | | | | 947 |
Exercise of stock options (in shares) | 48,312 | | | | | | |
Stock-based compensation expense | | 5,845 | | | | | 5,845 |
Vesting of restricted common stock awards (in shares) | 35,739 | | | | | | |
Unrealized gain (loss) on marketable debt securities | | | (231) | | | | (231) |
Net income (loss) | | | | | 7,819 | | 7,819 |
Balance, end of period at Sep. 30, 2020 | $ 6 | $ 1,043,892 | $ (48) | | $ (602,698) | | $ 441,152 |
Balance, end of period (in shares) at Sep. 30, 2020 | 62,187,700 | | | | | | |