Fair Value Measurements Fair Value of Outstanding Common Stock Warrants (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Amortization of Intangible Assets	$ 1.0	$ 0.9	$ 1.6	$ 1.8
Stock price	$ 18.72		$ 18.72		$ 16.25
Weighted average exercise price	0.10		$ 0.10		$ 0.10
Term (years)			7 years 2 months 1 day		7 years 8 months
Risk-free rate			2.09%		2.01%
Expected volatility			44.50%		50.20%
Historical volatilities period			10 years
Fair value of common stock warrants (in usd per share)	$ 18.46		$ 18.46		$ 16.17