SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Jan. 01, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Recently issued accounting pronouncements
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Retained earnings			$ 151,977		$ 122,713
Revenue Recognition
Unearned revenues			8,900		3,800
Cash payment received			27,600
Revenues recognized that was included in the deferred revenue balance			22,500
Trade accounts receivable
Allowance for doubtful accounts			1,900		$ 1,200
Development Services Contract
Revenue Recognition
Transaction price allocated to unsatisfied performance obligation			6,500
Fixed-fee Contract | COVID Services
Revenue Recognition
Transaction price allocated to unsatisfied performance obligation			12,800
Fixed-fee Contract | Subscription Services
Revenue Recognition
Transaction price allocated to unsatisfied performance obligation			$ 18,600
Fixed-fee Contract | Minimum | Subscription Services
Revenue Recognition
Expected timing to recognize revenue, term			1 year
Fixed-fee Contract | Maximum | Subscription Services
Revenue Recognition
Expected timing to recognize revenue, term			5 years
Cumulative Effect, Period of Adoption, Adjustment
Recently issued accounting pronouncements
Retained earnings	$ 300
State Enterprise | Revenues
Summary of Significant Accounting Policies
Prior period reclassification adjustment		$ (7,800)		$ (23,200)
State Enterprise | Cost of Revenues
Summary of Significant Accounting Policies
Prior period reclassification adjustment		(6,600)		(20,500)
Software & Services | Revenues
Summary of Significant Accounting Policies
Prior period reclassification adjustment		7,800		23,200
Software & Services | Cost of Revenues
Summary of Significant Accounting Policies
Prior period reclassification adjustment		$ 6,600		$ 20,500