Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	6 Months Ended
	Jul. 29, 2015	Jul. 31, 2015	Jun. 30, 2015	Jun. 30, 2014
Subsequent Event [Line Items]
Proceeds from the issuance of common stock			$ 285.7	$ 1.0
Subsequent Event [Member]
Subsequent Event [Line Items]
Stock-based compensation expense, accelerated vesting		$ 11.3
Shares sold to underwriters (in shares)	415,600
Shares sold to underwriters, price per share (in dollars per share)	$ 20.00
Proceeds from the issuance of common stock	$ 7.7