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Income Taxes - Reconciliation of statutory to effective income tax rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Federal Statutory Rate	21.00%	21.00%	35.00%
Permanent differences	(13.10%)	(25.70%)	57.50%
State taxes, net of Federal benefit	(0.10%)	3.50%	(6.60%)
Rate change	(3.50%)	(0.60%)	370.50%
Foreign earnings taxed at different rates than U.S.	(3.30%)	11.80%	(40.50%)
Valuation allowance	72.80%	81.20%	(401.40%)
Transition tax	0	(0.138)	0
Net operating loss expiration and remeasurement	(66.20%)	(75.80%)	0.00%
Changes in uncertain tax reserves	1.20%	(1.40%)	3.80%
Other	1.00%	0.10%	(4.60%)
Effective tax rate	9.80%	0.30%	13.70%

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Effective Income Tax Rate Reconciliation, Net Operating Loss Expiration and Remeasurement, Percent

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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