Business Overview - Revenues by Customer (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Concentration Risk [Line Items]
Revenue	$ 61,555	$ 51,459	$ 180,913	$ 158,495
Revenue from Contract with Customer | Customer concentration
Concentration Risk [Line Items]
Percent of total revenue			100.00%	100.00%
Department of Veterans Affairs
Concentration Risk [Line Items]
Revenue	27,496	24,783	$ 83,010	$ 74,402
Department of Veterans Affairs | Revenue from Contract with Customer | Customer concentration
Concentration Risk [Line Items]
Percent of total revenue			46.00%	47.00%
Department of Health and Human Services
Concentration Risk [Line Items]
Revenue	23,245	23,312	$ 66,748	$ 73,263
Department of Health and Human Services | Revenue from Contract with Customer | Customer concentration
Concentration Risk [Line Items]
Percent of total revenue			37.00%	46.00%
Department of Defense
Concentration Risk [Line Items]
Revenue	7,601	270	$ 22,103	$ 943
Department of Defense | Revenue from Contract with Customer | Customer concentration
Concentration Risk [Line Items]
Percent of total revenue			12.00%	1.00%
Customers with less than 10% share of total revenue
Concentration Risk [Line Items]
Revenue	$ 3,213	$ 3,094	$ 9,052	$ 9,887
Customers with less than 10% share of total revenue | Revenue from Contract with Customer | Customer concentration
Concentration Risk [Line Items]
Percent of total revenue			5.00%	6.00%