REVENUE RECOGNITION - Revenue by Customer Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Total revenue	$ 35,222	$ 50,160
Revenue from Contract with Customer, Product and Service Benchmark | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Total revenue	$ 35,222	$ 50,160
Concentration risk, percentage	100.00%	100.00%
Revenue from Contract with Customer, Product and Service Benchmark | Customer Concentration Risk | Firm fixed-price
Disaggregation of Revenue [Line Items]
Total revenue	$ 27,013	$ 41,277
Concentration risk, percentage	77.00%	82.00%
Revenue from Contract with Customer, Product and Service Benchmark | Customer Concentration Risk | Time-and-materials
Disaggregation of Revenue [Line Items]
Total revenue	$ 3,556	$ 2,916
Concentration risk, percentage	10.00%	6.00%
Revenue from Contract with Customer, Product and Service Benchmark | Customer Concentration Risk | Cost plus fixed fee
Disaggregation of Revenue [Line Items]
Total revenue	$ 4,653	$ 5,967
Concentration risk, percentage	13.00%	12.00%
Federal | Revenue from Contract with Customer, Product and Service Benchmark
Disaggregation of Revenue [Line Items]
Total revenue		$ 47,843
Federal | Revenue from Contract with Customer, Product and Service Benchmark | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Total revenue	$ 32,989
Concentration risk, percentage	94.00%	95.00%
State & local, and commercial | Revenue from Contract with Customer, Product and Service Benchmark | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,233	$ 2,317
Concentration risk, percentage	6.00%	5.00%
U.S. Department of Defense ("DoD") | Revenue from Contract with Customer, Product and Service Benchmark | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	68.00%	71.00%
Civilian | Revenue from Contract with Customer, Product and Service Benchmark | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	26.00%	24.00%