Common Stock - Additional Information (Details) $ / shares in Units, $ in Thousands				12 Months Ended
	Dec. 02, 2014 USD ($) $ / shares shares	Feb. 11, 2014 USD ($) $ / shares shares	Jan. 21, 2014	Dec. 31, 2016 USD ($) vote $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) shares	Sep. 20, 2016 $ / shares
Common Stock Capital Shares Reserved For Future Issuance [Line Items]
Reverse stock split ratio	0.5
Preferred stock, price per share (in dollars per share) | $ / shares							$ 3.37
Proceeds from issuance of common stock | $				$ 0	$ 12,650	$ 70,237
Shares of common stock into which warrants are exercisable (in shares)	871,840
Common stock, shares authorized (in shares)		200,000,000		200,000,000	200,000,000
Preferred stock, shares authorized (in shares)		5,000,000		5,000,000	5,000,000
Sale of common stock under securities purchase agreement (in shares)	1,743,680
Common stock, par value (in dollars per share) | $ / shares				$ 0.001	$ 0.001
Warrant issued, exercise price (in dollars per share) | $ / shares	$ 11.47
Common warrants exercise period	3 years
Net proceeds from offering | $	$ 18,200
Cowen and Company LLC [Member]
Common Stock Capital Shares Reserved For Future Issuance [Line Items]
Proceeds from issuance of common stock | $					$ 12,700
Common Stock
Common Stock Capital Shares Reserved For Future Issuance [Line Items]
Number of votes per share | vote				1
Issuance of common stock (in shares)					1,446,781	1,743,680
Initial Public Offering (IPO)
Common Stock Capital Shares Reserved For Future Issuance [Line Items]
Issuance of common stock (in shares)		5,750,000
Preferred stock, price per share (in dollars per share) | $ / shares		$ 10.00
Proceeds from issuance of common stock | $		$ 50,200
Initial Public Offering (IPO) | Common Stock
Common Stock Capital Shares Reserved For Future Issuance [Line Items]
Issuance of common stock (in shares)						14,010,424
Stock issued related to conversion of preferred stock (in shares)		8,260,444
Shares of common stock into which warrants are exercisable (in shares)		30,708
Initial Public Offering (IPO) | Underwriter
Common Stock Capital Shares Reserved For Future Issuance [Line Items]
Issuance of common stock (in shares)		750,000
Reverse Stock Split
Common Stock Capital Shares Reserved For Future Issuance [Line Items]
Reverse stock split ratio			0.1575
Common Stock Warrants
Common Stock Capital Shares Reserved For Future Issuance [Line Items]
Common stock, par value (in dollars per share) | $ / shares	$ 0.001
Warrant issued, exercise price (in dollars per share) | $ / shares	$ 15.00