Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 2020

Stockholders' Equity

Schedule of common reserved shares of common stock for issuance

	June 30,
	2020	December 31,
	(unaudited)	2019
Options issued and outstanding	4,455,101	3,902,675
Inducement options issued and outstanding	3,392	74
Options available for grant under stock option plans	710,299	479,829
Restricted stock unit awards issued and outstanding	5,613	5,613
Warrants issued and outstanding	16,991,395	19,421,892
Series A convertible preferred stock	473,565	473,565
Series B convertible preferred stock	—	985,500
Series B-2 convertible preferred stock	1,431,460	1,931,350
Total	24,070,825	27,200,498