Revenue, Contract Balances (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Revenue [Abstract]
Revenue recognized	$ 1,000	$ 500
Contract liabilities [Abstract]
Customer pre-payments	126		$ 232
Deferred revenue, current	479		700
Deferred revenue, non-current	120		219
Total contract liabilities	$ 725		$ 1,151