Balance Sheet Information and Fair Value - Additional Information (Detail) - USD ($)	12 Months Ended
	Feb. 28, 2017	Feb. 29, 2016	Feb. 28, 2015
Property, Plant and Equipment [Line Items]
Available-for-sale securities, gross realized gains	$ 1,100,000	$ 0	$ 0
Impairment of long-lived assets	0	1,200,000	0
Depreciation, amortization and impairment expense	16,431,000	13,300,000	8,631,000
Equity method investment in privately-held company	$ 1,800,000	$ 1,600,000
Percentage of ownership interest	23.00%	24.00%
Proportionate share of investee's losses, equity method	$ 300,000	$ 400,000	0
Cost method investment in privately-held company	2,300,000	1,600,000
Property and equipment
Property, Plant and Equipment [Line Items]
Depreciation, amortization and impairment expense	$ 9,200,000	$ 7,700,000	$ 5,200,000