Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Tax Credit Carryforward [Line Items]
Valuation allowance, deferred tax asset, increase (decrease), amount	$ 14,943	$ 22,818
Unrecognized tax benefits	4,690	$ 3,201	$ 1,954
Unrecognized tax benefits that would impact effective tax rate	4,407
Unrecognized tax benefits, income tax penalties and interest expense	538
Domestic Tax Authority
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	207,768
Operating loss carryforwards, subject to expiration	22,907
State and Local Jurisdiction
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	146,121
Operating loss carryforwards, subject to expiration	129,143
Foreign Tax Authority
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	1,321
Deferred income tax asset	$ 1,131
Israel Tax Authority | Foreign Tax Authority | VSL | Minimum
Tax Credit Carryforward [Line Items]
Tax rate for amount of dividends distributed, other than complete liquidation	10.00%
Israel Tax Authority | Foreign Tax Authority | VSL | Maximum
Tax Credit Carryforward [Line Items]
Tax rate for amount of dividends distributed, other than complete liquidation	25.00%
Research Tax Credit Carryforward | Domestic Tax Authority
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	$ 1,412
Retention | Domestic Tax Authority
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	24
Foreign Tax Credit | Domestic Tax Authority
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	190
Ireland Employment | Domestic Tax Authority
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	$ 16