Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2023

Equity [Abstract]

Summary of Series B Preferred Stock and Accretion of Dividends

The following table summarizes Series B convertible preferred stock and the accretion of dividend activity for the three months ended March 31, 2023 and 2022 (in thousands):

	Three Months Ended March 31,
	2023		2022
Series B Convertible Preferred Stock:
Balance at beginning of period	$	25,323	$	24,117
Cumulative dividends on Series B convertible preferred stock		313		298
Balance at end of period	$	25,636	$	24,415
Number of Common Shares Issuable Upon Conversion:
Number of shares at beginning of period		6,331		6,029
Cumulative dividends on Series B convertible preferred stock		78		75
Number of shares at end of period		6,409		6,104

Summary of Outstanding Warrants

Below is the summary of outstanding warrants as of March 31, 2023:

Warrant Type	Number of Shares Issuable Upon Exercise		Weighted Average Exercise Price		Issue Date	Expiration Date
April 21 Funds Warrants		275,000	$	3.50	May 5, 2020	May 5, 2023

Summary of Common Stock Reserved for Future Issuance

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance as of March 31, 2023 was as follows:

Exercise of outstanding stock options, vesting of restricted stock units ("RSUs"), vesting of      performance stock units ("PSUs"), and issuance of RSUs vested but not released	1,556,124
Employee Stock Purchase Plan	293,888
Shares of common stock available for grant under the 2011 Plan	416,955
Warrants to purchase common stock	275,000
Shares of common stock issuable upon conversion of Series B convertible preferred stock	7,541,449
Total	10,083,416