Revenue Recognition - Schedule of Accounts Receivable, Net (Detail) - USD ($)	Dec. 31, 2019	Mar. 31, 2019
Accounts Receivable Net Current [Abstract]
Billed receivables	$ 51,020,000	$ 58,410,000
Allowance for doubtful accounts	(2,333,000)	(5,508,000)
Contract assets	17,500,000	18,434,000
Accounts receivable, net	$ 66,187,000	$ 71,336,000