Marketable Securities and Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		6 Months Ended
	Jul. 31, 2017	Jul. 31, 2014	Sep. 30, 2017	Mar. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate carrying amount of other investments			$ 12,600	$ 7,200
Additional investment in private medical device company	$ 6,000		$ 6,400
ECP Entwicklungsgesellschaft mbH
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payments to acquire businesses, cash paid		$ 13,000
Potential payouts payments		$ 15,000