Warrants - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	7 Months Ended	12 Months Ended
	Apr. 30, 2011	Oct. 31, 2011	Dec. 31, 2015	Dec. 31, 2014	Apr. 15, 2015
Class Of Warrant Or Right [Line Items]
Warrants issued to purchase stock		615,658
Warrants expire date		2021-04
Warrant remeasurement expense, net			$ 26,077	$ 566
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
Carrying value of warrants			25,900
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
Carrying value of warrants			$ 1,200