Subsequent Event (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended				12 Months Ended
	Mar. 31, 2016	Jan. 31, 2016	Feb. 28, 2015	Aug. 31, 2014	Dec. 31, 2014
Subsequent Event [Line Items]
Proceeds from issuance of common stock and warrants, net of issuance cost			$ 10.9
Common Stock
Subsequent Event [Line Items]
Issuance of common stock, net of offering costs (shares)			6,043,955	300,000	2,600,000
Common Stock
Subsequent Event [Line Items]
Exercise price (USD per share)			$ 1.82	$ 1.97
Class of warrant number of securities called by each warrant (shares)			0.5
Warrants, period from issuance in which warrants are exercisable			6 months 1 day
Warrant expiration period			7 years
Warrants issued (in shares)			3,021,977
Subsequent Event
Subsequent Event [Line Items]
Aggregate offering price		$ 10.0
Proceeds from issuance of common stock and warrants, net of issuance cost	$ 7.8	$ 2.2
Subsequent Event | Common Stock
Subsequent Event [Line Items]
Common stock, maximum number of shares to be purchased (shares)		11,363,640
Issuance of common stock, net of offering costs (shares)		2,528,411
Subsequent Event | Common Stock
Subsequent Event [Line Items]
Maximum number of warrants to be purchased (shares)		5,681,818
Exercise price (USD per share)		$ 0.88
Class of warrant number of securities called by each warrant (shares)		0.5
Warrants, period from issuance in which warrants are exercisable		6 months 1 day
Warrant expiration period		7 years
Warrants issued (in shares)		1,264,204