Condensed Consolidated Statements of Stockholder's Equity - USD ($) $ in Thousands | Total | Common Stock | Additional Paid-in Capital | Accumulated Other Comprehensive Income (Loss) | Accumulated Deficit |
Balance at beginning of period (in shares) at Dec. 31, 2018 | | | 30,745,000 | | | |
Balance at beginning of period at Dec. 31, 2018 | $ 120,994 | | $ 31 | $ 308,766 | $ (41) | $ (187,762) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | |
Issuance of common stock and exercise of stock options (in shares) | | | 417,000 | | | |
Issuance of common stock and exercise of stock options | 4,467 | | | 4,467 | | |
Stock-based compensation expense | 4,014 | | | 4,014 | | |
Unrealized gain (loss) on short-term investments | 77 | | | | 77 | |
Net loss | (10,805) | | | | | (10,805) |
Balance at end of period (in shares) at Mar. 31, 2019 | | | 31,162,000 | | | |
Balance at end of period at Mar. 31, 2019 | 118,747 | | $ 31 | 317,247 | 36 | (198,567) |
Balance at beginning of period (in shares) at Dec. 31, 2018 | | | 30,745,000 | | | |
Balance at beginning of period at Dec. 31, 2018 | 120,994 | | $ 31 | 308,766 | (41) | (187,762) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | |
Unrealized gain (loss) on short-term investments | 135 | | | | | |
Net loss | (35,037) | | | | | |
Balance at end of period (in shares) at Sep. 30, 2019 | | | 31,510,000 | | | |
Balance at end of period at Sep. 30, 2019 | 110,883 | | $ 32 | 333,556 | 94 | (222,799) |
Balance at beginning of period (in shares) at Mar. 31, 2019 | | | 31,162,000 | | | |
Balance at beginning of period at Mar. 31, 2019 | 118,747 | | $ 31 | 317,247 | 36 | (198,567) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | |
Issuance of common stock and exercise of stock options (in shares) | | | 307,000 | | | |
Issuance of common stock and exercise of stock options | 4,964 | | | 4,964 | | |
Stock-based compensation expense | 5,680 | | | 5,680 | | |
Unrealized gain (loss) on short-term investments | 61 | | | | 61 | |
Net loss | (11,384) | | | | | (11,384) |
Balance at end of period (in shares) at Jun. 30, 2019 | | | 31,469,000 | | | |
Balance at end of period at Jun. 30, 2019 | 118,068 | | $ 31 | 327,891 | 97 | (209,951) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | |
Issuance of common stock and exercise of stock options (in shares) | | | 41,000 | | | |
Issuance of common stock and exercise of stock options | 408 | | $ 1 | 407 | | |
Stock-based compensation expense | 5,258 | | | 5,258 | | |
Unrealized gain (loss) on short-term investments | (3) | | | | (3) | |
Net loss | (12,848) | | | | | (12,848) |
Balance at end of period (in shares) at Sep. 30, 2019 | | | 31,510,000 | | | |
Balance at end of period at Sep. 30, 2019 | 110,883 | | $ 32 | 333,556 | 94 | (222,799) |
Balance at beginning of period (in shares) at Dec. 31, 2019 | | | 32,235,000 | | | |
Balance at beginning of period at Dec. 31, 2019 | 118,058 | [1] | $ 32 | 348,729 | 53 | (230,756) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | |
Issuance of common stock and exercise of stock options (in shares) | | | 302,000 | | | |
Issuance of common stock and exercise of stock options | 3,101 | | $ 1 | 3,100 | | |
Stock-based compensation expense | 4,253 | | | 4,253 | | |
Unrealized gain (loss) on short-term investments | (19) | | | | (19) | |
Net loss | (17,533) | | | | | (17,533) |
Balance at end of period (in shares) at Mar. 31, 2020 | | | 32,537,000 | | | |
Balance at end of period at Mar. 31, 2020 | 107,860 | | $ 33 | 356,082 | 34 | (248,289) |
Balance at beginning of period (in shares) at Dec. 31, 2019 | | | 32,235,000 | | | |
Balance at beginning of period at Dec. 31, 2019 | 118,058 | [1] | $ 32 | 348,729 | 53 | (230,756) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | |
Unrealized gain (loss) on short-term investments | (31) | | | | | |
Net loss | (52,122) | | | | | |
Balance at end of period (in shares) at Sep. 30, 2020 | | | 32,716,000 | | | |
Balance at end of period at Sep. 30, 2020 | 81,378 | | $ 33 | 364,201 | 22 | (282,878) |
Balance at beginning of period (in shares) at Mar. 31, 2020 | | | 32,537,000 | | | |
Balance at beginning of period at Mar. 31, 2020 | 107,860 | | $ 33 | 356,082 | 34 | (248,289) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | |
Issuance of common stock and exercise of stock options (in shares) | | | 108,000 | | | |
Issuance of common stock and exercise of stock options | 728 | | | 728 | | |
Stock-based compensation expense | 3,586 | | | 3,586 | | |
Unrealized gain (loss) on short-term investments | 61 | | | | 61 | |
Net loss | (23,124) | | | | | (23,124) |
Balance at end of period (in shares) at Jun. 30, 2020 | | | 32,645,000 | | | |
Balance at end of period at Jun. 30, 2020 | 89,111 | | $ 33 | 360,396 | 95 | (271,413) |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | |
Issuance of common stock and exercise of stock options (in shares) | | | 71,000 | | | |
Issuance of common stock and exercise of stock options | 276 | | | 276 | | |
Stock-based compensation expense | 3,529 | | | 3,529 | | |
Unrealized gain (loss) on short-term investments | (73) | | | | (73) | |
Net loss | (11,465) | | | | | (11,465) |
Balance at end of period (in shares) at Sep. 30, 2020 | | | 32,716,000 | | | |
Balance at end of period at Sep. 30, 2020 | $ 81,378 | | $ 33 | $ 364,201 | $ 22 | $ (282,878) |
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[1] | Amounts have been derived from the December 31, 2019 audited consolidated financial statements included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission. |