Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Changes in Redemption Value of Convertible Preferred Stock

The changes in the redemption value of the redeemable convertible preferred stock for the year ended December 31, 2015 was as follows:

	Year Ended December 31, 2015
Redeemable Convertible Preferred Stock	(in thousands)
Series B	$	46,976
Series B-1		36,961
Series C		52,832
Series D		237,246
Total adjustment to redemption value on redeemable convertible preferred stock	$	374,015