Net Loss Per Share - Earnings Per Share Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended								11 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 10, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Class of Stock [Line Items]
Net loss	$ (5,909)	$ (10,293)	$ (14,630)	$ (11,029)	$ (7,447)	$ (12,657)	$ (13,382)	$ (10,563)	$ (4,552)	$ (35,246)	$ (43,399)	$ (41,154)	$ (29,544)
Weighted average common shares outstanding - basic and diluted (in shares)											39,852,624	32,156,060	31,376,603
Basic and diluted net loss per share (in dollars per share)											$ (1.09)	$ (1.28)	$ (0.94)
Class A Common Stock
Class of Stock [Line Items]
Net loss											$ (30,075)	$ (25,259)	$ (18,016)
Weighted average common shares outstanding - basic and diluted (in shares)											27,617,350	19,736,342	19,133,028
Basic and diluted net loss per share (in dollars per share)											$ (1.09)	$ (1.28)	$ (0.94)
Class B Common Stock
Class of Stock [Line Items]
Net loss											$ (13,324)	$ (15,895)	$ (11,528)
Weighted average common shares outstanding - basic and diluted (in shares)											12,235,274	12,419,718	12,243,575
Basic and diluted net loss per share (in dollars per share)											$ (1.09)	$ (1.28)	$ (0.94)