Income Taxes - Summary of Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Net operating losses	$ 83,143	$ 85,510
Credit carryovers	19,903	19,903
Depreciation and amortization	13,944	14,922
Accruals and reserves	609	808
Capital loss carryover	85	100
Other	3,114	3,660
Total deferred tax assets	120,798	124,903
Less valuation allowance	(120,798)	(124,903)
Net deferred tax assets	$ 0	$ 0