Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Preferred stock and convertible preferred stock

Preferred stock and convertible preferred stock consist of the following:

	December 31,
	2017		2016
Preferred stock, $0.001 par value; 5,000,000 shares authorized at December 31, 2017 and 2016; no shares issued and outstanding at December 31, 2017 and 2016	$	—	$	—
Series B convertible preferred stock, $0.001 par value, 147,000 shares designated at December 31, 2017 and 2016, and 500 shares issued and outstanding at December 31, 2017 and 2016	1		1
Series D convertible preferred stock, $0.001 par value, 21,300 and zero shares designated at December 31, 2017 and 2016, respectively, 14,052.93 and 17,202.65 shares issued and outstanding at December 31, 2017 and 2016, respectively	14		17
Series E convertible preferred stock, $0.001 par value, 7,000 and zero shares designated at December 31, 2017 and 2016, respectively, and 7,000 and zero shares issued and outstanding at December 31, 2017 and 2016, respectively	7		—
Series F convertible preferred stock, $0.001 par value, 10,621 and zero shares designated at December 31, 2017 and 2016, respectively, and 7,927.05 and zero shares issued and outstanding at December 31, 2017 and 2016, respectively	8		—

Reserved Authorized Shares of Common Stock for Future Issuance

At December 31, 2017, the Company has reserved authorized shares of common stock for future issuance as follows:

Warrants	459,375
Outstanding stock options	80,537
Possible future issuance under inducement plan	12,500
Possible future issuance under stock option plans	618,247
Possible future issuance under employee stock purchase plan	58
Total	1,170,717