Revenues - Disaggregation of Revenues (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Revenues		$ 6,155	$ 6,796	$ 18,557	$ 22,731
Subscriptions [Member]
Disaggregation Of Revenue [Line Items]
Revenues		3,832	4,383	11,595	15,654
Strategic Agreements [Member]
Disaggregation Of Revenue [Line Items]
Revenues		2,323	2,413	6,962	7,077
United States of America [Member]
Disaggregation Of Revenue [Line Items]
Revenues		4,799	5,051	14,252	17,133
United Kingdom [Member]
Disaggregation Of Revenue [Line Items]
Revenues		690	898	2,328	2,802
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenues	[1]	$ 666	$ 847	$ 1,977	$ 2,796

[1] No individual country within the “Other” category accounted for 10% or more of revenues for any period presented.