Statements of Stockholders' Equity - USD ($) $ in Thousands | Total | Common Stock | Additional Paid-In-Capital | Accumulated Deficit |
Beginning balance at Dec. 31, 2018 | $ 23,620 | $ 32 | $ 230,475 | $ (206,887) |
Beginning balance, shares at Dec. 31, 2018 | | 32,119,227 | | |
Issuance of common shares under at-the-market sales agreement | 6,627 | $ 5 | 6,622 | |
Issuance of common shares under at-the-market sales agreement, shares | | 4,660,966 | | |
Exercise of stock options | 1 | | 1 | |
Exercise of stock options, shares | | 2,727 | | |
Share-based compensation expense | 1,247 | | 1,247 | |
Net loss | (15,404) | | | (15,404) |
Ending balance at Mar. 31, 2019 | 16,091 | $ 37 | 238,345 | (222,291) |
Ending balance, shares at Mar. 31, 2019 | | 36,782,920 | | |
Beginning balance at Dec. 31, 2018 | 23,620 | $ 32 | 230,475 | (206,887) |
Beginning balance, shares at Dec. 31, 2018 | | 32,119,227 | | |
Net loss | (27,674) | | | |
Ending balance at Sep. 30, 2019 | 9,759 | $ 41 | 244,279 | (234,561) |
Ending balance, shares at Sep. 30, 2019 | | 41,149,781 | | |
Beginning balance at Mar. 31, 2019 | 16,091 | $ 37 | 238,345 | (222,291) |
Beginning balance, shares at Mar. 31, 2019 | | 36,782,920 | | |
Issuance of common shares under at-the-market sales agreement | 1,273 | $ 1 | 1,272 | |
Issuance of common shares under at-the-market sales agreement, shares | | 945,974 | | |
Issuance of common shares under employee stock purchase plan | 15 | | 15 | |
Issuance of common shares under employee stock purchase plan, shares | | 17,252 | | |
Share-based compensation expense | 1,256 | | 1,256 | |
Net loss | (5,734) | | | (5,734) |
Ending balance at Jun. 30, 2019 | 12,901 | $ 38 | 240,888 | (228,025) |
Ending balance, shares at Jun. 30, 2019 | | 37,746,146 | | |
Issuance of common shares under at-the-market sales agreement | 2,419 | $ 3 | 2,416 | |
Issuance of common shares under at-the-market sales agreement, shares | | 3,370,000 | | |
Vesting of restricted stock units, shares | | 20,000 | | |
Exercise of stock options | 5 | | 5 | |
Exercise of stock options, shares | | 13,635 | | |
Share-based compensation expense | 970 | | 970 | |
Net loss | (6,536) | | | (6,536) |
Ending balance at Sep. 30, 2019 | 9,759 | $ 41 | 244,279 | (234,561) |
Ending balance, shares at Sep. 30, 2019 | | 41,149,781 | | |
Beginning balance at Dec. 31, 2019 | 11,157 | $ 44 | 248,770 | (237,657) |
Beginning balance, shares at Dec. 31, 2019 | | 44,413,372 | | |
Issuance of common shares under at-the-market sales agreement | 1,193 | $ 1 | 1,192 | |
Issuance of common shares under at-the-market sales agreement, shares | | 455,186 | | |
Share-based compensation expense | 1,001 | | 1,001 | |
Net loss | (2,911) | | | (2,911) |
Ending balance at Mar. 31, 2020 | 10,440 | $ 45 | 250,963 | (240,568) |
Ending balance, shares at Mar. 31, 2020 | | 44,868,558 | | |
Beginning balance at Dec. 31, 2019 | 11,157 | $ 44 | 248,770 | (237,657) |
Beginning balance, shares at Dec. 31, 2019 | | 44,413,372 | | |
Net loss | (11,098) | | | |
Ending balance at Sep. 30, 2020 | 8,124 | $ 48 | 256,831 | (248,755) |
Ending balance, shares at Sep. 30, 2020 | | 48,227,442 | | |
Beginning balance at Mar. 31, 2020 | 10,440 | $ 45 | 250,963 | (240,568) |
Beginning balance, shares at Mar. 31, 2020 | | 44,868,558 | | |
Issuance of common shares under at-the-market sales agreement | 1,607 | $ 1 | 1,606 | |
Issuance of common shares under at-the-market sales agreement, shares | | 800,170 | | |
Vesting of restricted stock units, shares | | 512,550 | | |
Exercise of stock options | 72 | | 72 | |
Exercise of stock options, shares | | 58,333 | | |
Issuance of common shares under employee stock purchase plan | 31 | | 31 | |
Issuance of common shares under employee stock purchase plan, shares | | 35,359 | | |
Share-based compensation expense | 891 | | 891 | |
Net loss | (5,754) | | | (5,754) |
Ending balance at Jun. 30, 2020 | 7,287 | $ 46 | 253,563 | (246,322) |
Ending balance, shares at Jun. 30, 2020 | | 46,274,970 | | |
Issuance of common shares under at-the-market sales agreement | 2,285 | $ 2 | 2,283 | |
Issuance of common shares under at-the-market sales agreement, shares | | 1,382,564 | | |
Vesting of restricted stock units, shares | | 375,025 | | |
Exercise of stock options | 144 | | 144 | |
Exercise of stock options, shares | | 194,883 | | |
Share-based compensation expense | 841 | | 841 | |
Net loss | (2,433) | | | (2,433) |
Ending balance at Sep. 30, 2020 | $ 8,124 | $ 48 | $ 256,831 | $ (248,755) |
Ending balance, shares at Sep. 30, 2020 | | 48,227,442 | | |