CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands | Total | Common Stock | Additional Paid-In Capital | Accumulated Other Comprehensive Income (Loss) | Accumulated Deficit | Series A Preferred StockSeries A Convertible Preferred Stock | Series B Preferred Stock | Series B Convertible Preferred Stock | Series B Convertible Preferred StockCommon Stock | Series B Convertible Preferred StockAdditional Paid-In Capital | Series A Convertible Preferred Stock | Series A Convertible Preferred StockSeries A Convertible Preferred Stock | Series A Convertible Preferred StockCommon Stock | Series A Convertible Preferred StockAdditional Paid-In Capital |
Balance (in shares) at Dec. 31, 2019 | | 933,423 | | | | 796 | | | | | | | | |
Balance at Dec. 31, 2019 | $ (4,085) | $ 9 | $ 360,926 | $ (126) | $ (364,894) | $ 0 | | | | | | | | |
Increase (decrease) in stockholders' equity | | | | | | | | | | | | | | |
Non-cash stock-based compensation expense | 597 | | 597 | | | | | | | | | | | |
Issuance of common stock for 401k match (in shares) | | 17,518 | | | | | | | | | | | | |
Issuance of common stock for 401(k) match | 86 | | 86 | | | | | | | | | | | |
Issuance of common stock for convertible securities (in shares) | | 207,296 | | | | | | | 718,750 | | | (796) | 99,500 | |
Issuance of common stock for convertible securities | 1,658 | $ 2 | 1,656 | | | | | | $ 7 | $ (7) | | | $ 2 | $ (2) |
Issuance of common stock for restricted stock units (in shares) | | 6,006 | | | | | | | | | | | | |
Taxes paid on employees' behalf related to vesting of stock awards | (17) | | (17) | | | | | | | | | | | |
Issuance of common stock for stock offerings (in shares) | | 1,348,285 | | | | | | | | | | | | |
Issuance of common stock for stock offerings, net of offering costs | 5,305 | $ 13 | 5,292 | | | | | | | | | | | |
Reclassification of warrant liability to equity | 15,934 | | 15,934 | | | | | | | | | | | |
Effect of foreign currency translation and unrealized loss on investments | (42) | | | (42) | | | | | | | | | | |
Net loss | (7,564) | | | | (7,564) | | | | | | | | | |
Balance (in shares) at Sep. 30, 2020 | | 3,330,778 | | | | 0 | | | | | | | | |
Balance at Sep. 30, 2020 | $ 11,872 | $ 33 | 384,465 | (168) | (372,458) | $ 0 | | | | | | | | |
Convertible Preferred Stock, outstanding (in shares) at Dec. 31, 2019 | | | | | | | 5,750 | | | | | | | |
Convertible Preferred Stock, outstanding at Dec. 31, 2019 | | | | | | | $ 0 | | | | | | | |
Increase (Decrease) in Temporary Equity [Roll Forward] | | | | | | | | | | | | | | |
Issuance of common stock upon conversion of Series B Convertible Preferred Stock | (5,750) | | | | | | | | | | | | | |
Convertible Preferred Stock, outstanding (in shares) at Sep. 30, 2020 | | | | | | | 0 | | | | | | | |
Convertible Preferred Stock, outstanding at Sep. 30, 2020 | | | | | | | $ 0 | | | | | | | |
Balance (in shares) at Jun. 30, 2020 | | 1,972,798 | | | | 0 | | | | | | | | |
Balance at Jun. 30, 2020 | $ 8,487 | $ 20 | 378,924 | (167) | (370,290) | $ 0 | | | | | | | | |
Increase (decrease) in stockholders' equity | | | | | | | | | | | | | | |
Non-cash stock-based compensation expense | 243 | | 243 | | | | | | | | | | | |
Issuance of common stock for 401k match (in shares) | | 3,689 | | | | | | | | | | | | |
Issuance of common stock for 401(k) match | 23 | | 23 | | | | | | | | | | | |
Issuance of common stock for restricted stock units (in shares) | | 6,006 | | | | | | | | | | | | |
Taxes paid on employees' behalf related to vesting of stock awards | (17) | | (17) | | | | | | | | | | | |
Issuance of common stock for stock offerings (in shares) | | 1,348,285 | | | | | | | | | | | | |
Issuance of common stock for stock offerings, net of offering costs | 5,305 | $ 13 | 5,292 | | | | | | | | | | | |
Effect of foreign currency translation and unrealized loss on investments | (1) | | | (1) | | | | | | | | | | |
Net loss | (2,168) | | | | (2,168) | | | | | | | | | |
Balance (in shares) at Sep. 30, 2020 | | 3,330,778 | | | | 0 | | | | | | | | |
Balance at Sep. 30, 2020 | 11,872 | $ 33 | 384,465 | (168) | (372,458) | $ 0 | | | | | | | | |
Convertible Preferred Stock, outstanding (in shares) at Jun. 30, 2020 | | | | | | | 0 | | | | | | | |
Convertible Preferred Stock, outstanding at Jun. 30, 2020 | | | | | | | $ 0 | | | | | | | |
Convertible Preferred Stock, outstanding (in shares) at Sep. 30, 2020 | | | | | | | 0 | | | | | | | |
Convertible Preferred Stock, outstanding at Sep. 30, 2020 | | | | | | | $ 0 | | | | | | | |
Balance (in shares) at Dec. 31, 2020 | | 3,334,048 | | | | 0 | | | | | | | | |
Balance at Dec. 31, 2020 | 9,532 | $ 33 | 384,758 | (159) | (375,100) | $ 0 | | | | | | | | |
Increase (decrease) in stockholders' equity | | | | | | | | | | | | | | |
Non-cash stock-based compensation expense | 1,185 | | 1,185 | | | | | | | | | | | |
Issuance of common stock for 401k match (in shares) | | 9,747 | | | | | | | | | | | | |
Issuance of common stock for 401(k) match | 86 | | 86 | | | | | | | | | | | |
Issuance of common stock for convertible securities (in shares) | | 481,973 | | | | | | | | | | | | |
Issuance of common stock for convertible securities | 3,856 | $ 5 | 3,851 | | | | | $ 0 | | | $ 0 | | | |
Issuance of common stock for restricted stock units (in shares) | | 12,219 | | | | | | | | | | | | |
Taxes paid on employees' behalf related to vesting of stock awards | (102) | | (102) | | | | | | | | | | | |
Issuance of common stock for stock offerings (in shares) | | 1,040,000 | | | | | | | | | | | | |
Issuance of common stock for stock offerings, net of offering costs | 11,993 | $ 11 | 11,982 | | | | | | | | | | | |
Reclassification of warrant liability to equity | 15,934 | | | | | | | | | | | | | |
Effect of foreign currency translation and unrealized loss on investments | (11) | | | (11) | | | | | | | | | | |
Net loss | (8,051) | | | | (8,051) | | | | | | | | | |
Balance (in shares) at Sep. 30, 2021 | | 4,877,987 | | | | 0 | | | | | | | | |
Balance at Sep. 30, 2021 | 18,488 | $ 49 | 401,760 | (170) | (383,151) | $ 0 | | | | | | | | |
Convertible Preferred Stock, outstanding (in shares) at Dec. 31, 2020 | | | | | | | 0 | | | | | | | |
Convertible Preferred Stock, outstanding at Dec. 31, 2020 | | | | | | | $ 0 | | | | | | | |
Convertible Preferred Stock, outstanding (in shares) at Sep. 30, 2021 | | | | | | | 0 | | | | | | | |
Convertible Preferred Stock, outstanding at Sep. 30, 2021 | | | | | | | $ 0 | | | | | | | |
Balance (in shares) at Jun. 30, 2021 | | 4,868,466 | | | | 0 | | | | | | | | |
Balance at Jun. 30, 2021 | 20,462 | $ 49 | 401,319 | (153) | (380,753) | $ 0 | | | | | | | | |
Increase (decrease) in stockholders' equity | | | | | | | | | | | | | | |
Non-cash stock-based compensation expense | 436 | | 436 | | | | | | | | | | | |
Issuance of common stock for 401k match (in shares) | | 2,857 | | | | | | | | | | | | |
Issuance of common stock for 401(k) match | 24 | | 24 | | | | | | | | | | | |
Issuance of common stock for restricted stock units (in shares) | | 6,664 | | | | | | | | | | | | |
Issuance of common stock for restricted stock units | | | 0 | | | | | | | | | | | |
Taxes paid on employees' behalf related to vesting of stock awards | (19) | | (19) | | | | | | | | | | | |
Effect of foreign currency translation and unrealized loss on investments | (17) | | | (17) | | | | | | | | | | |
Net loss | (2,398) | | | | (2,398) | | | | | | | | | |
Balance (in shares) at Sep. 30, 2021 | | 4,877,987 | | | | 0 | | | | | | | | |
Balance at Sep. 30, 2021 | $ 18,488 | $ 49 | $ 401,760 | $ (170) | $ (383,151) | $ 0 | | | | | | | | |
Convertible Preferred Stock, outstanding (in shares) at Jun. 30, 2021 | | | | | | | 0 | | | | | | | |
Convertible Preferred Stock, outstanding at Jun. 30, 2021 | | | | | | | $ 0 | | | | | | | |
Convertible Preferred Stock, outstanding (in shares) at Sep. 30, 2021 | | | | | | | 0 | | | | | | | |
Convertible Preferred Stock, outstanding at Sep. 30, 2021 | | | | | | | $ 0 | | | | | | | |