Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Operating loss carryforward valuation allowance	$ 20,800,000
Valuation allowance	5,538,000	$ 7,919,000
Impact of California NOL adjustment	(13,500,000)
Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward valuation allowance	2,800,000
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	58,700,000
Federal | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward amount	1,800,000
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	14,400,000.0
State | Research Tax Credit Carryforward | California
Operating Loss Carryforwards [Line Items]
Tax credit carryforward amount	$ 1,600,000