Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	$ 381	$ 347	$ 736	$ 727
Selling, General and Administrative Expense [Member]
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	350	321	677	675
Research and Development Expense [Member]
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	$ 31	$ 26	$ 59	$ 52