Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating Loss Carryforwards [Line Items]
Deferred income tax expense (benefit)	$ (471,000)	$ 157,000	$ (2,659,000)	$ 952,000
Deferred tax liabilities	18,680,000		18,680,000
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Taxable income (loss)	(7,780,000)	65,400,000	(17,680,000)	38,800,000
Current income tax expense (benefit)	0	$ 777,000	0	$ 777,000
Operating loss carryforwards	266,400,000		266,400,000
Federal and state research and development tax credits	6,770,000		$ 6,770,000
Expiration date of U.S. federal income tax loss carryforwards			2022
Domestic Tax Authority | Stock Compensation Deductions
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	53,400,000		$ 53,400,000
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Current income tax expense (benefit)	(120,000)		(213,000)
Operating loss carryforwards	$ 117,900,000		$ 117,900,000