Balance Sheet Information - Summary of Long-term Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Liabilities Noncurrent [Abstract]
Executive deferred compensation plan	$ 1,797	$ 1,652
Reserve for uncertain tax positions	842	842
Deferred rent	223	166
Deferred revenues	43	74
Long-term obligations under capital leases	0	2
Total long-term liabilities	$ 2,905	$ 2,736