Income Taxes - Components of Income Tax (Benefit) Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Expected Statutory benefit	$ (5,257)	$ (7,627)
Other non-deductible expenses	133	256
Change in valuation allowance	4,674	6,572
Research credits	(504)	0
Tax rate differential - foreign vs. U.S.	1,073	791
State income taxes, net of federal benefit	18	23
Prior year true-up	(45)	(93)
Exchange gain	(1)	16
Total income tax expense (benefit)	$ 91	$ (62)