Accumulated Other Comprehensive Income (Loss) - Changes in Balances of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 240,201
Other comprehensive income (loss) before reclassifications	(237)	$ (814)	$ (1,714)
Amounts reclassified to net loss	90	972	653
Other comprehensive income (loss)	(147)	158	(1,061)
Ending balance	231,963	240,201
Unrealized Gain (Loss) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(1,021)	(1,428)	(426)
Other comprehensive income (loss) before reclassifications	(134)	(565)	(1,655)
Amounts reclassified to net loss	90	972	653
Other comprehensive income (loss)	(44)	407	(1,002)
Ending balance	(1,065)	(1,021)	(1,428)
Unrealized Gain (Loss) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(310)	(61)	(2)
Other comprehensive income (loss) before reclassifications	(103)	(249)	(59)
Amounts reclassified to net loss	0	0	0
Other comprehensive income (loss)	(103)	(249)	(59)
Ending balance	(413)	(310)	(61)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(1,331)	(1,489)	(428)
Ending balance	$ (1,478)	$ (1,331)	$ (1,489)