Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2019

Equity [Abstract]

Summary of Common Shares Reserved for Future Issuance

The Company had reserved shares of common stock for possible future issuance as of December 31, 2019 and 2018 as follows:

	December 31,
	2019	2018
Common stock warrants outstanding	2,838,454	5,815,283
Stock options outstanding	9,044,304	8,796,212
Restricted stock units outstanding	400,315	454,382
Shares available for issuance pursuant to Convertible Notes	40,649,225	40,649,225
Shares available for future grants of awards under the 2015 Incentive Compensation Plan	4,557	1,943,085
Shares available for future grants of awards under the 2018 Omnibus Incentive Compensation Plan	2,483,664	3,224,425
Shares available under the 2000 Employee Stock Purchase Plan	622,476	825,537
Total shares of common stock reserved for issuance	56,042,995	61,708,149