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Income Taxes (Details Textual) - USD ($)	12 Months Ended
Income Taxes (Details Textual) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2017	Dec. 31, 2016
Tax Credit Carryforward [Line Items]
Effective income tax rate, foreign dertived intangible income, percent	13.125%
Valuation allowance, deferred tax asset, increase (decrease), amount	$ 15,826,000	$ 8,623,000
Deferred tax assets	137,000
Deferred tax assets, valuation allowance	39,365,000	27,702,000
Accumulated deficit	(137,968,000)	(109,390,000)
Unrecognized tax benefits	1,954,000	3,682,000		$ 2,106,000
Unrecognized tax benefits that would impact effective tax rate	1,431,000
Unrecognized tax benefits, income tax penalties and interest expense	93,000
Undistributed earnings of foreign subsidiaries	678,000
Undistributed earnings of foreign subsidiaries subject to transition tax	285
Accounting Standards Update 2016-09
Tax Credit Carryforward [Line Items]
Deferred tax assets			$ 3,796,000
Deferred tax assets, valuation allowance			2,493,000
Accumulated deficit			$ 1,302,000
Domestic Tax Authority
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	54,872,000
Domestic Tax Authority \| Accounting Standards Update 2018-02
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	31,965,000	$ 22,907,000
State and Local Jurisdiction
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	57,530,000
Foreign Tax Authority
Tax Credit Carryforward [Line Items]
Operating loss carryforwards	$ 1,204,000
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	$ 1,412,000
Retention \| Domestic Tax Authority
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	24,000
Foreign Tax Credit \| Domestic Tax Authority
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	190,000
Ireland Employment \| Domestic Tax Authority
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	$ 78,000