Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2022

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 and nine months ended September 30, 2022 and 2021 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
Series B Convertible Preferred Stock:
Balance at beginning of period	$	24,715	$	23,539	$	24,117	$	22,969
Cumulative dividends on Series B convertible preferred stock		304		289		902		859
Balance at end of period	$	25,019	$	23,828	$	25,019	$	23,828
Number of Common Shares Issuable Upon Conversion:
Number of shares at beginning of period		6,179		5,885		6,029		5,742
Cumulative dividends on Series B convertible preferred stock		76		72		226		215
Number of shares at end of period		6,255		5,957		6,255		5,957

Summary of Outstanding Warrants

Below is the summary of outstanding warrants as of September 30, 2022:

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 September 30, 2022 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	1,301,289
Employee Stock Purchase Plan	293,888
Shares of common stock available for grant under the 2011 Plan	858,346
Warrants to purchase common stock	275,000
Shares of common stock issuable upon conversion of Series B convertible preferred stock	7,541,449
Total	10,269,972