Significant Accounting Policies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Mar. 31, 2014	Sep. 30, 2013
Accounting Policies [Abstract]
Accrued distributor price adjustments	$ 4,207	$ 3,866
Expected instrument utilization period	3 years
Period of review of accounts individually	90 days
Likelihood percentage of tax benefit being recognized upon ultimate settlement	50.00%
Tax benefits recognized from uncertain tax positions measurement	Greater than 50% likely of being ultimately realized upon settlement