Statement of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands | Common Stock [Member] | Additional Paid-in Capital [Member] | Retained Earnings [Member] | Total |
Beginning balance, value at Dec. 31, 2018 | $ 15 | $ 139,693 | $ (121,962) | $ 17,746 |
Beginning balance, shares at Dec. 31, 2018 | 15,034 | | | |
Stock-based compensation | | 694 | | 694 |
Stock-based compensation, shares | 298 | | | |
Net loss | | | (3,534) | (3,534) |
Ending balance, value at Mar. 31, 2019 | $ 15 | 140,387 | (125,496) | 14,906 |
Ending balance, shares at Mar. 31, 2019 | 15,332 | | | |
Beginning balance, value at Dec. 31, 2018 | $ 15 | 139,693 | (121,962) | 17,746 |
Beginning balance, shares at Dec. 31, 2018 | 15,034 | | | |
Warrant modification | | | | 0 |
Ending balance, value at Sep. 30, 2019 | $ 17 | 148,368 | (132,216) | 16,169 |
Ending balance, shares at Sep. 30, 2019 | 17,074 | | | |
Beginning balance, value at Mar. 31, 2019 | $ 15 | 140,387 | (125,496) | 14,906 |
Beginning balance, shares at Mar. 31, 2019 | 15,332 | | | |
Registered direct offering of common stock, net of commissions and expenses | $ 2 | 6,395 | | 6,397 |
Registered direct offering of common stock, net of commissions and expenses, shares | 1,675 | | | |
Stock-based compensation | | 788 | | 788 |
Stock-based compensation, shares | 67 | | | |
Net loss | | | (3,634) | (3,634) |
Ending balance, value at Jun. 30, 2019 | $ 17 | 147,570 | (129,130) | 18,457 |
Ending balance, shares at Jun. 30, 2019 | 17,074 | | | |
Stock-based compensation | | 798 | | 798 |
Stock-based compensation, shares | | | | |
Net loss | | | (3,086) | (3,086) |
Ending balance, value at Sep. 30, 2019 | $ 17 | 148,368 | (132,216) | 16,169 |
Ending balance, shares at Sep. 30, 2019 | 17,074 | | | |
Beginning balance, value at Dec. 31, 2019 | $ 17 | 149,017 | (135,262) | 13,772 |
Beginning balance, shares at Dec. 31, 2019 | 17,117 | | | |
Stock-based compensation | $ 1 | 628 | | 629 |
Stock-based compensation, shares | 420 | | | |
Warrant Exercise | | 164 | | 164 |
Warrant exercise, shares | 189 | | | |
Warrant modification | | 139 | | 139 |
Net loss | | | (3,645) | (3,645) |
Ending balance, value at Mar. 31, 2020 | $ 18 | 149,948 | (138,907) | 11,059 |
Ending balance, shares at Mar. 31, 2020 | 17,726 | | | |
Beginning balance, value at Dec. 31, 2019 | $ 17 | 149,017 | (135,262) | 13,772 |
Beginning balance, shares at Dec. 31, 2019 | 17,117 | | | |
Warrant modification | | | | 139 |
Ending balance, value at Sep. 30, 2020 | $ 21 | 170,975 | (146,264) | 24,732 |
Ending balance, shares at Sep. 30, 2020 | 20,971 | | | |
Beginning balance, value at Mar. 31, 2020 | $ 18 | 149,948 | (138,907) | 11,059 |
Beginning balance, shares at Mar. 31, 2020 | 17,726 | | | |
Stock-based compensation | | 766 | | 766 |
Stock-based compensation, shares | 43 | | | |
Net loss | | | (3,779) | (3,779) |
Underwritten public offering of common stock, net of commissions and expenses | $ 2 | 9,393 | | 9,395 |
Underwritten public offering of common stock, net of commissions and expenses, shares | 2,024 | | | |
Stock option exercise | | 137 | | 137 |
Stock option exercise, shares | 33 | | | |
Ending balance, value at Jun. 30, 2020 | $ 20 | 160,244 | (142,686) | 17,578 |
Ending balance, shares at Jun. 30, 2020 | 19,826 | | | |
Stock-based compensation | | 829 | | 829 |
Stock-based compensation, shares | | | | |
Warrant Exercise | | 738 | | 738 |
Warrant exercise, shares | 196 | | | |
Net loss | | | (3,578) | (3,578) |
Stock option exercise | | 645 | | 645 |
Stock option exercise, shares | 103 | | | |
At-the-market sale of stock, net of commissions and expenses | $ 1 | 8,519 | | 8,520 |
At-the-market sale of stock, net of commissions and expenses, shares | 846 | | | |
Ending balance, value at Sep. 30, 2020 | $ 21 | $ 170,975 | $ (146,264) | $ 24,732 |
Ending balance, shares at Sep. 30, 2020 | 20,971 | | | |