Other Balance Sheet Accounts - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Balance Sheet Related Disclosures [Abstract]
Depreciation and amortization of equipment and leasehold improvements	$ 1.6	$ 1.6	$ 1.6
Amortization of licensed technology rights and patent application costs	0.4	0.4	0.7
Estimated annual amortization for these assets in 2014	0.2
Estimated annual amortization for these assets in 2015	0.2
Estimated annual amortization for these assets in 2016	0.2
Estimated annual amortization for these assets in 2017	0.2
Estimated annual amortization for these assets in 2018	$ 0.2