Revenue Revenue by Product Category and Geography (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) region category	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 29,072	$ 25,362	$ 25,013
Number Of Product Categories | category	3
Number Of Geographic Regions | region	3
United States
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 20,073	16,588	16,639
United Kingdom
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	7,693	7,527	6,453
India
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,306	1,247	1,921
Software license and appliances
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	6,762	4,903	5,814
Service
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	22,310	20,459	19,199
Subscription, maintenance and support
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	19,555	18,249	17,132
Professional services and other
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 2,755	$ 2,210	$ 2,067