Stockholders' Equity (Details)				12 Months Ended
	Dec. 22, 2020	Jun. 03, 2019	Jul. 31, 2017 item	Dec. 31, 2019 shares	Dec. 31, 2020 shares	Aug. 28, 2018 shares
Stockholders' Equity
Number of voting rights entitled for each share of common stock held | item			1
Reverse stock split ratio		0.0143		1
Shares of common stock reserved for issuance
Options issued and outstanding				3,902,675	4,456,748
Options available for grant under stock option plans				479,829	596,597
RSUs awards issued and outstanding				5,613	5,613
Warrants issued and outstanding				19,421,892	7,205,454
Convertible preferred stock						9,580
Total				27,200,498	12,379,304
Minimum
Stockholders' Equity
Reverse stock split ratio	0.5
Maximum
Stockholders' Equity
Reverse stock split ratio	0.05
Inducement options issued and outstanding
Shares of common stock reserved for issuance
Options issued and outstanding				74	114,892
Blank check preferred stock
Stockholders' Equity
Common stock, shares authorized					4,475,074
Series A convertible preferred stock
Shares of common stock reserved for issuance
Convertible preferred stock				473,565
Series B convertible preferred stock
Shares of common stock reserved for issuance
Convertible preferred stock				985,500
Series B-2 convertible preferred stock
Shares of common stock reserved for issuance
Convertible preferred stock				1,931,350
Common Stock
Stockholders' Equity
Common stock, shares authorized					204,475,074
Common Stock | Common stock - voting
Stockholders' Equity
Common stock, shares authorized				150,000,000	150,000,000
Common Stock | Common stock - non-voting
Stockholders' Equity
Common stock, shares authorized				50,000,000	50,000,000