Significant Customers and Geographic Data Revenues and Accounts Receivable by Customers (Details) - Customer Concentration Risk - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Revenues | Customer A
Revenue, Major Customer [Line Items]
Revenues	$ 4,945
Current Receivables | Customer B
Revenue, Major Customer [Line Items]
Accounts Receivable			$ 841
Current Receivables | Customer C
Revenue, Major Customer [Line Items]
Accounts Receivable		$ 677	782
Current Receivables | Customer D
Revenue, Major Customer [Line Items]
Accounts Receivable			$ 692
Current Receivables | Customer E
Revenue, Major Customer [Line Items]
Accounts Receivable		550
Current Receivables | Customer F
Revenue, Major Customer [Line Items]
Accounts Receivable		$ 471