Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Jun. 30, 2021	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 68,981	$ 53,644	$ 109,402	$ 178,383	$ 242,433	$ 179,917	$ 159,218
Services
Disaggregation of Revenue [Line Items]
Total revenue	62,955	49,003	101,061	164,016	221,548	161,180	143,581
Products
Disaggregation of Revenue [Line Items]
Total revenue	$ 6,026	$ 4,641	$ 8,341	$ 14,367	20,885	18,737	15,637
Security Solutions
Disaggregation of Revenue [Line Items]
Total revenue					123,534	117,312	101,923
Security Solutions | Services
Disaggregation of Revenue [Line Items]
Total revenue					102,649	100,422	86,286
Security Solutions | Products
Disaggregation of Revenue [Line Items]
Total revenue					20,885	16,890	15,637
Secure Networks
Disaggregation of Revenue [Line Items]
Total revenue					118,899	62,605	57,295
Secure Networks | Services
Disaggregation of Revenue [Line Items]
Total revenue					118,899	60,758	57,295
Secure Networks | Products
Disaggregation of Revenue [Line Items]
Total revenue					0	1,847	0
Firm fixed-price | Security Solutions
Disaggregation of Revenue [Line Items]
Total revenue					104,534	98,379	80,316
Firm fixed-price | Secure Networks
Disaggregation of Revenue [Line Items]
Total revenue					107,770	53,324	51,313
Time-and-materials | Security Solutions
Disaggregation of Revenue [Line Items]
Total revenue					12,433	12,617	14,100
Time-and-materials | Secure Networks
Disaggregation of Revenue [Line Items]
Total revenue					28	838	469
Cost plus fixed fee | Security Solutions
Disaggregation of Revenue [Line Items]
Total revenue					6,567	6,316	7,507
Cost plus fixed fee | Secure Networks
Disaggregation of Revenue [Line Items]
Total revenue					11,101	8,443	5,513
Federal | Security Solutions
Disaggregation of Revenue [Line Items]
Total revenue					114,159	109,410	92,336
Federal | Secure Networks
Disaggregation of Revenue [Line Items]
Total revenue					$ 118,717	$ 62,267	$ 56,921
Federal | Revenue from Contract with Customer, Product and Service Benchmark | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk, percentage					96.10%	95.40%	93.70%
U.S. Department of Defense | Revenue from Contract with Customer, Product and Service Benchmark | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk, percentage					74.00%	65.00%	65.00%
Civilian | Revenue from Contract with Customer, Product and Service Benchmark | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk, percentage					22.00%	30.00%	29.00%
State & Local, and Commercial | Security Solutions
Disaggregation of Revenue [Line Items]
Total revenue					$ 9,375	$ 7,902	$ 9,587
State & Local, and Commercial | Secure Networks
Disaggregation of Revenue [Line Items]
Total revenue					$ 182	$ 338	$ 374