Property and Equipment - Schedule of Property and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Property Plant And Equipment [Abstract]
Computer equipment and purchased software	$ 3,591	$ 3,748
Machinery and equipment	701	654
Furniture and fixtures	578	546
Leasehold improvements	899	884
Total	5,769	5,832
Less accumulated depreciation	(4,651)	(4,551)
Property and equipment, net	$ 1,118	$ 1,281