Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2017 USD ($) Customer	Dec. 31, 2016 Customer	Dec. 31, 2017 USD ($) Customer	Dec. 31, 2016 Customer	Mar. 31, 2017 USD ($) Customer
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Maturities of short term investment interest-bearing securities			90 days
Accounts receivable due period			30 days
Minimum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment			2 years
Maximum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment			7 years
Computer Software Property and Equipment [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Amortization period of computer software			5 years
Customer Concentration Risk [Member] | Sales Revenue, Net [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Maximum customer risk percentage	10.00%	10.00%	10.00%	10.00%
Number of customer | Customer	0	0	0	0
Credit Concentration Risk [Member] | Accounts Receivable [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Maximum customer risk percentage			10.00%		10.00%
Number of customer | Customer			0		0
Private Equity Funds [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Investment	$ 2,250,000		$ 2,250,000
Impairment recorded on investment			1,169,000		$ 284,000
Fair Value, Inputs, Level 2 [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Transfer of assets	0		0		0
Fair Value, Inputs, Level 3 [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Transfer of assets	$ 0		$ 0		$ 0