Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Increase in valuation allowance, excluding Tax Act impact	$ 2,483	$ 4,036	$ 45,512
Income tax (benefit) provision	289	(177)	(2,164)
Impact from the change in tax law	0	0	2,632
Remeasurement of our U.S. federal deferred tax assets and liabilities			1,200
Release of valuation allowance due to the Tax Act	$ 0	$ 0	$ 1,398
Statutory federal rate	21.00%	21.00%	34.00%
Valuation allowance	$ 111,193	$ 109,625	$ 107,046	$ 115,689
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	242,500
State and Local Jurisdiction | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development tax credit carryforwards	400
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	415,100
Federal | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development tax credit carryforwards	$ 800