Income Taxes (Details 2) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Carry forward tax losses	$ 35,051	$ 28,033
Research and development carry forward expenses-temporary differences	1,294	1,567
Accrual and reserves	290	241
Right-of-use asset	433
Total deferred tax assets	37,068	29,841
Deferred tax liabilities:
Right-of-use liability	(431)
Net deferred tax assetsDeferred	36,635
Valuation allowance	(36,392)	(29,655)	$ (26,311)	$ (22,560)
Net deferred tax assets	$ 243	$ 186