Stockholders' Equity - Additional Information (Details) - USD ($)		12 Months Ended
	Aug. 10, 2015	Dec. 31, 2015	Dec. 31, 2014
Class Of Stock [Line Items]
Common stock issuable upon preferred stock conversion	1,667,683
Common shares issuable upon conversion of warrants	1,250,764
Deemed dividend to convertible preferred shareholders		$ 24,890,000
Common stock dividends		0
Series D and E Preferred Shares
Class Of Stock [Line Items]
Deemed dividend to convertible preferred shareholders	$ 24,900,000	$ 24,900,000
Convertible Preferred Stock
Class Of Stock [Line Items]
Preferred Stock Shares Issued And Outstanding		0	54,841,000
Initial Public Offering
Class Of Stock [Line Items]
Issuance of common stock in connection with underwritten public offering, net of issuance costs, (in shares)	17,900,000
Sale of stock, price per share	$ 14.00
Proceeds from issuance initial public offering	$ 221,300,000
Offering expense	$ 7,500,000
Shares sold by shareholders in initial public offering	417,732
Convertible preferred stock into common stock	54,840,767