Accumulated Other Comprehensive Income (Loss) - Changes in Balances of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (428)	$ 861	$ (616)
Other comprehensive income (loss) before reclassifications	(1,714)	746	936
Amounts reclassified to net loss	653	(2,035)	541
Other comprehensive income (loss)	(1,061)	(1,289)	1,477
Ending Balance	(1,489)	(428)	861
Unrealized Gain (Loss) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(426)	691	(559)
Other comprehensive income (loss) before reclassifications	(1,655)	712	652
Amounts reclassified to net loss	653	(1,829)	598
Other comprehensive income (loss)	(1,002)	(1,117)	1,250
Ending Balance	(1,428)	(426)	691
Unrealized Gain (Loss) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(2)	170	(57)
Other comprehensive income (loss) before reclassifications	(59)	34	284
Amounts reclassified to net loss	0	(206)	(57)
Other comprehensive income (loss)	(59)	(172)	227
Ending Balance	$ (61)	$ (2)	$ 170