Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Contingency [Line Items]
Deferred tax asset, net change in total valuation allowance increase (decrease) during period	$ 21,100,000	$ (1,000,000)	$ 10,900,000
Unrecognized tax benefits	1,182,000	666,000	3,019,000	$ 532,000
Unrecognized tax benefits which would affect company's effective tax rate due to valuation allowance	0
Interest and penalties accrued	$ 0	$ 0	$ 0
Minimum
Income Tax Contingency [Line Items]
Percentage of change in ownership	50.00%
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 71,500,000
Operating loss carryforwards expiration year	2030
Federal | 2010
Income Tax Contingency [Line Items]
Open tax year	2010
Federal | 2014
Income Tax Contingency [Line Items]
Open tax year	2016
Federal | Research and Development Tax Credits
Income Tax Contingency [Line Items]
Reduction to tax credit carryforwards	$ 1,700,000
Tax credit carryforward, expiration	2030
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 14,300,000
Operating loss carryforwards expiration year	2030
State | 2010
Income Tax Contingency [Line Items]
Open tax year	2010
State | 2014
Income Tax Contingency [Line Items]
Open tax year	2016
State | Research and Development Tax Credits
Income Tax Contingency [Line Items]
Reduction to tax credit carryforwards	$ 2,900,000