Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Statutory income tax rate	34.00%	34.00%	34.00%
Net operating loss carryforwards, US	$ 165,500,000
Accrued income tax for interest or penalties	0	$ 0	$ 0
Stock-based Compensation Tax Deductions
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 5,300,000
Earliest Tax Year
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards expiration year	2027
Open tax year for review by taxing authorities	2010
Latest Tax Year
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards expiration year	2035
Open tax year for review by taxing authorities	2016