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Summary of Significant Accounting Policies - Concentration of Credit Risk (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Jun. 30, 2020
Medicare | Revenues | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk percentage	60.00%	53.00%
Medicare | Accounts Receivable | Credit Concentration Risk
Concentration Risk [Line Items]
Concentration risk percentage	31.00%		28.00%
Previously Reported
Concentration Risk [Line Items]
Cost of goods and services		$ 12.4

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