Revenue Recognition - Schedule of Accounts Receivable, Net (Detail) - USD ($)	Sep. 30, 2020	Mar. 31, 2020
Accounts Receivable Net Current [Abstract]
Billed receivables	$ 58,224,000	$ 51,208,000
Allowance for doubtful accounts	(6,172,000)	(5,133,000)
Unbilled receivables	21,043,000	19,692,000
Accounts receivable, net	$ 73,095,000	$ 65,767,000

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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Amount of allowance for credit loss on accounts receivable, classified as current.

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Amounts due for billed services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the Company and, at a minimum, one other party. An example would be amounts billed to customers under contracts or programs but not paid as of the balance sheet date.

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Amount received for services rendered and products shipped, but not yet billed, for non-contractual agreements due within one year or the normal operating cycle, if longer.

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