Summary of Significant Accounting Policies (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Total stock-based compensation expense	$ 873	$ 3,412
Research and Development Expense [Member]
Total stock-based compensation expense	14	106
General and Administrative Expenses [Member]
Total stock-based compensation expense	$ 859	$ 3,306