Summary of Significant Accounting Policies - Summary of Revenue by Region (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Disaggregation Of Revenue [Line Items]
Revenue	$ 56,891	$ 55,477	$ 171,334	$ 155,338
Service
Disaggregation Of Revenue [Line Items]
Revenue	$ 56,891	$ 55,477	$ 171,334	$ 155,338
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | Service
Disaggregation Of Revenue [Line Items]
Percentage of Revenue	100.00%	100.00%	100.00%	100.00%
United States
Disaggregation Of Revenue [Line Items]
Revenue	$ 41,741	$ 40,074	$ 120,706	$ 108,502
United States | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Disaggregation Of Revenue [Line Items]
Percentage of Revenue	73.00%	72.00%	70.00%	70.00%
United Kingdom
Disaggregation Of Revenue [Line Items]
Revenue	$ 10,779	$ 10,722	$ 37,020	$ 35,703
United Kingdom | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Disaggregation Of Revenue [Line Items]
Percentage of Revenue	19.00%	19.00%	22.00%	23.00%
Canada
Disaggregation Of Revenue [Line Items]
Revenue	$ 3,065	$ 3,334	$ 9,052	$ 7,282
Canada | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Disaggregation Of Revenue [Line Items]
Percentage of Revenue	5.00%	6.00%	5.00%	5.00%
Other
Disaggregation Of Revenue [Line Items]
Revenue	$ 1,306	$ 1,347	$ 4,556	$ 3,851
Other | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Disaggregation Of Revenue [Line Items]
Percentage of Revenue	2.00%	2.00%	3.00%	2.00%
International
Disaggregation Of Revenue [Line Items]
Revenue	$ 15,150	$ 15,403	$ 50,628	$ 46,836
International | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Disaggregation Of Revenue [Line Items]
Percentage of Revenue	27.00%	28.00%	30.00%	30.00%