Income Taxes - Narrative (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Net deferred tax assets	$ 71,641	$ 48,425
Net operating loss carryovers	48,912	$ 34,954
Federal Alternative Minimum Tax Credit carryforwards	$ 200
Net operating loss carryforward limitation on use percentage ownership change minimum	50.00%
Unrecognized tax benefits that would not impact effective tax rate	$ 1,700
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Net operating loss carryovers	143,500
Internal Revenue Service (IRS) | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development tax credits carryforward	12,800
Internal Revenue Service (IRS) | Stock options
Operating Loss Carryforwards [Line Items]
Net operating loss carryovers	19,400
California
Operating Loss Carryforwards [Line Items]
Net operating loss carryovers	133,300
California | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development tax credits carryforward	5,400
California | Stock options
Operating Loss Carryforwards [Line Items]
Net operating loss carryovers	$ 14,500