Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Provision (benefit) for income taxes	$ (943)	$ 55	$ 84	$ (708)	$ 124	$ 84	$ 74	$ 75	$ (1,512)	$ 357
U.S. federal statutory income tax rate									21.00%	21.00%
Change in valuation allowance									$ 2,700	$ 9,200
Unremitted earnings of the subsidiaries outside of the United States	8,600								8,600
Tax cuts and jobs act, incomplete accounting, transition tax for accumulated foreign earnings, provisional income tax expense									600
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	288,800								288,800
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	176,200								176,200
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	18,000								18,000
Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	10,200								10,200
Research Tax Credit Carryforward | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	$ 8,000								$ 8,000