Commitments and Contingencies - Additional Information (Detail) £ in Thousands	12 Months Ended
	Mar. 31, 2016 USD ($) Contracts $ / £	Mar. 31, 2016 GBP (£)	Mar. 31, 2015 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2008 GBP (£)
Commitments And Contingencies Disclosure [Abstract]
Expiry date of operating leases	2021	2021
Operating leases, Rent expense, Minimum rentals	$ 2,923,000		$ 2,111,000	$ 1,293,000
Capital Leased Assets, Gross Cost	2,098,000		1,024,000
Capital Leases, Balance Sheet, Assets by Major Class, Net	$ 1,930,000		737,000
Research and development grant funding from Scottish Enterprise | £					£ 1,791
Claims from grant | £		£ 1,790
Number of forward exchange contracts | Contracts	9
Forward exchange contracts sold	$ 500,000
Forward exchange contracts exchange rate pounds sterling to US dollar | $ / £	1.50
Total liabilities measured at fair value	$ 190,000		199,000
Gain (loss) on foreign currency derivatives recorded in earnings, net	$ 0		$ 0	$ 0