Note 8 - Stock-based Compensation - Options Outstanding (Details) | 6 Months Ended |
Jun. 30, 2023 $ / shares shares |
Options outstanding (in shares) | shares | 13,455 |
Options outstanding, weighted average remaining contractual life (Year) | 8 years 11 months 1 day |
Options outstanding, weighted average exercise price (in dollars per share) | $ 1,071 |
Options exercisable (in shares) | shares | 4,698 |
Options excercisable, weighted average remaining contractual life (Year) | 7 years 5 months 12 days |
Exercise Price Range 1 [Member] | |
Per share exercise price, lower limit (in dollars per share) | $ 15 |
Per share exercise price, upper limit (in dollars per share) | $ 1,764 |
Options outstanding (in shares) | shares | 11,470 |
Options outstanding, weighted average remaining contractual life (Year) | 9 years 5 months 15 days |
Options outstanding, weighted average exercise price (in dollars per share) | $ 52 |
Options exercisable (in shares) | shares | 2,892 |
Options excercisable, weighted average remaining contractual life (Year) | 8 years 7 months 13 days |
Exercise Price Range 2 [Member] | |
Per share exercise price, lower limit (in dollars per share) | $ 2,712 |
Per share exercise price, upper limit (in dollars per share) | $ 2,730 |
Options outstanding (in shares) | shares | 49 |
Options outstanding, weighted average remaining contractual life (Year) | 7 years 5 months 23 days |
Options outstanding, weighted average exercise price (in dollars per share) | $ 2,714 |
Options exercisable (in shares) | shares | 18 |
Options excercisable, weighted average remaining contractual life (Year) | 6 years 2 months 23 days |
Exercise Price Range 3 [Member] | |
Per share exercise price, lower limit (in dollars per share) | $ 3,000 |
Per share exercise price, upper limit (in dollars per share) | $ 5,004 |
Options outstanding (in shares) | shares | 1,001 |
Options outstanding, weighted average remaining contractual life (Year) | 5 years 10 months 24 days |
Options outstanding, weighted average exercise price (in dollars per share) | $ 4,081 |
Options exercisable (in shares) | shares | 897 |
Options excercisable, weighted average remaining contractual life (Year) | 5 years 8 months 4 days |
Exercise Price Range 4 [Member] | |
Per share exercise price, lower limit (in dollars per share) | $ 5,400 |
Per share exercise price, upper limit (in dollars per share) | $ 6,900 |
Options outstanding (in shares) | shares | 378 |
Options outstanding, weighted average remaining contractual life (Year) | 6 years 2 months 8 days |
Options outstanding, weighted average exercise price (in dollars per share) | $ 6,247 |
Options exercisable (in shares) | shares | 378 |
Options excercisable, weighted average remaining contractual life (Year) | 6 years 2 months 8 days |
Exercise Price Range 5 [Member] | |
Per share exercise price, lower limit (in dollars per share) | $ 9,720 |
Per share exercise price, upper limit (in dollars per share) | $ 12,000 |
Options outstanding (in shares) | shares | 399 |
Options outstanding, weighted average remaining contractual life (Year) | 5 years 8 months 12 days |
Options outstanding, weighted average exercise price (in dollars per share) | $ 10,955 |
Options exercisable (in shares) | shares | 355 |
Options excercisable, weighted average remaining contractual life (Year) | 5 years 6 months 10 days |
Exercise Price Range 6 [Member] | |
Per share exercise price, lower limit (in dollars per share) | $ 18,120 |
Options outstanding (in shares) | shares | 158 |
Options outstanding, weighted average remaining contractual life (Year) | 3 years 5 months 12 days |
Options outstanding, weighted average exercise price (in dollars per share) | $ 18,120 |
Options exercisable (in shares) | shares | 158 |
Options excercisable, weighted average remaining contractual life (Year) | 3 years 5 months 12 days |