Convertible Preferred Stock - Additional Information (Details) - USD ($)				12 Months Ended
	Mar. 10, 2015	Jul. 15, 2014	Dec. 24, 2013	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 12, 2016	Dec. 31, 2013
Class Of Stock [Line Items]
Proceeds from issuance of convertible preferred stock, net of offering costs					$ 43,679,000	$ 5,575,000
Change in fair value of forward sale contract						$ 1,444,000
Adjustments to additional paid in capital, increase in carrying amount of convertible preferred stock					$ 228,000
Convertible preferred stock conversion ratio				100.00%
Vote of percentage of the outstanding convertible preferred stock				62.00%
Convertible preferred stock, terms of conversion				The convertible preferred stock was automatically convertible into shares of common stock at the then-current conversion rate upon (i) a vote of 62% of the outstanding Series B convertible preferred stock, or (ii) the closing of a firm commitment underwritten public offering that met aggregate gross proceed and pricing terms.
Non-cumulative dividend rate				8.00%
Dividends declared prior to converting the shares to common stock				$ 0
Common Stock
Class Of Stock [Line Items]
Number of shares issued				5,482,000
Conversion of preferred stock, conversion unit					753,000
Convertible preferred stock converted into common stock				0			7,172,496
Series A Convertible Preferred Stock
Class Of Stock [Line Items]
Proceeds from issuance of convertible preferred stock, net of offering costs		$ 5,600,000	$ 5,100,000
Number of shares issued		1,067,592	971,928
Preferred stock issuance price		$ 5.25	$ 5.25
Additional shares offered on forward contract		837,594	837,594
Forward sale contract price per share		$ 7.56	$ 5.25
Fair value of forward sale contract at issuance			$ 440,000
Fair value of forward sale contract at settlement		$ 1,900,000
Discount on convertible preferred shares		$ 531,000
Number of shares issued at discount		229,998
Conversion of preferred stock, conversion unit					2,173,000
Preferred stock, par value					$ 0.0001
Adjustments to additional paid in capital, increase in carrying amount of convertible preferred stock					$ (228,000)
Convertible preferred stock converted into common stock					2,172,520
Preferred stock, shares outstanding				0	2,172,520
Liquidation preference price per share				$ 5.25
Series A Convertible Preferred Shares
Class Of Stock [Line Items]
Conversion of preferred stock, conversion unit	1				(2,173,000)
Preferred stock, par value	$ 0.0001
Deemed dividend per share	$ 0.11
Adjustments to additional paid in capital, increase in carrying amount of convertible preferred stock	$ 228,000
Preferred stock, shares outstanding						2,173,000		972,000
Series B Convertible Preferred Stock
Class Of Stock [Line Items]
Number of shares issued	4,929,948
Preferred stock issuance price	$ 8.93
Preferred stock, par value	$ 0.0001				$ 0.0001
Gross proceeds from issuance of preferred stock	$ 44,000,000
Offering costs	$ 321,000
Convertible preferred stock converted into common stock					4,999,976
Preferred stock, shares outstanding				0	4,999,976
Liquidation preference price per share				$ 8.93
Series B Convertible Preferred Stock | Minimum
Class Of Stock [Line Items]
Preferred stock, shares outstanding				342,857
Class A-1 Common
Class Of Stock [Line Items]
Aggregate distribution amount				$ 1,000,000
Class A-1 Common | Common Stock
Class Of Stock [Line Items]
Conversion of preferred stock, conversion unit					(165,000)