CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Accounts receivable and unbilled, net with related parties	$ 1.2	$ 2.3
Pre-funded study costs with related parties	1.5	3.9
Advanced billings with related parties	$ 4.2	$ 7.6
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock shares authorized	5,000,000	5,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock shares authorized	250,000,000	250,000,000
Common stock shares issued	39,692,999	40,662,856
Common stock shares outstanding	39,692,999	40,662,856