Note 11 - Net Loss Per Share Attributable to Common Stockholders - Anti-dilutive Securities (Details) - shares shares in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
Potentially dilutive common shares (in shares)		49,819	46,705
Unvested Stock [Member]
Potentially dilutive common shares (in shares)	[1]	1,904	1,662
Convertible Preferred Stocks [Member]
Potentially dilutive common shares (in shares)		46,533	30,754
Common Stock Warrants [Member]
Potentially dilutive common shares (in shares)		1,382	2,207
IPO Warrants [Member]
Potentially dilutive common shares (in shares)	[2]	0	12,082

[1] Does not include 9.4 million shares and 8.3 million shares of unvested restricted stock and restricted stock units for the years ended December 31, 2022 and 2021 because the performance conditions had not yet been satisfied as of December 31, 2022 and 2021, respectively.

[2] The IPO Warrants were issued in connection with our initial public offering in 2015 and expired July 24, 2022.