Description of Business and Summary of Significant Accounting Policies - Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Thousands, unless otherwise specified					3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2014 Unrealized Gains on Investments [Member]	Mar. 31, 2013 Unrealized Gains on Investments [Member]	Mar. 31, 2014 Foreign Currency Translation Adjustment [Member]	Mar. 31, 2013 Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (139)	$ (139)	$ (67)	$ 77	$ (6)	$ 1	$ (133)	$ 76
Other comprehensive income before reclassifications					(2)	0	(3)	(189)
Amounts reclassified from accumulated other comprehensive income to other income on the statement of operations					0	0	5	45
Ending Balance	$ (139)	$ (139)	$ (67)	$ 77	$ (8)	$ 1	$ (131)	$ (68)