Financing Arrangements (Convertible Senior Notes) - Additional Information (Detail)	3 Months Ended	6 Months Ended			12 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2015 USD ($) $ / shares shares	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) $ / shares	Dec. 31, 2012 USD ($)
Debt Disclosure [Abstract]
Convertible senior notes		$ 0	$ 0		$ 0	$ 112,500,000
Convertible senior notes interest rate						3.75%
Convertible senior notes convertible latest date			Aug. 15, 2019
Debt conversion, maximum number of common stock shares | shares			15,000,000
Conversion price per share | $ / shares			$ 7.50		$ 7.50
Convertible senior notes, transactional fees		$ 0				$ 3,537,000
Amount of shares issued upon conversion | shares			15,000,000
Amount of discount on convertible notes					$ 108,955,000
Convertible senior notes, unamortized discount			$ 3,395,000		$ 3,395,000
Convertible senior notes, total interest and amortization expense recognized	$ 1,248,000			$ 2,506,000
Initial conversion rate, number of common stock issuable		0.1333