Warrant Liabilities - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	7 Months Ended	9 Months Ended
	Apr. 30, 2011	Sep. 30, 2014	Oct. 31, 2011	Sep. 30, 2015	Sep. 30, 2014	Apr. 15, 2015	Apr. 14, 2015
Class Of Warrant Or Right [Line Items]
Warrants issued to purchase stock			615,658
Warrants expire date			2021-04
Warrant remeasurement expense, net		$ 157		$ 26,077	$ 282
Warrants exercisable date			2015-04
Government fund grant date			Apr. 15, 2015
Common Stock Warrants
Class Of Warrant Or Right [Line Items]
Fair value of warrants						$ 25,900
Warrant remeasurement expense, net				25,000
Series A-1
Class Of Warrant Or Right [Line Items]
Warrants issued to purchase stock	24,235
Warrants expire date	2021-04
Series B
Class Of Warrant Or Right [Line Items]
Warrants issued to purchase stock	83,771
Warrants expire date	2016-04
Convertible Preferred Stock Warrants
Class Of Warrant Or Right [Line Items]
Fair value of warrants							$ 1,200
Warrant remeasurement expense, net				$ 1,100