Stockholders' Equity (Deficit) - Class of Stock Disclosures (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015
Class of stock information
Preferred stock, shares authorized	5,000,000	5,000,000	0
Preferred stock, par value per share (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares outstanding	0	0	0
Authorized common stock	250,000,000	250,000,000	250,000,000
Common stock, par value	$ 0.001	$ 0.001	$ 0.001
Common stock issued	93,390,172	93,390,172	75,760,061
Common stock, shares outstanding	93,390,172	93,390,172	75,760,061
Offering
Proceeds from issuance of common stock, net of issuance costs		$ 45,737
IPO and Underwriters' Option
Offering
Shares issued	17,239,143
Proceeds from issuance of common stock, net of issuance costs	$ 44,800