Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Sep. 30, 2017	Mar. 31, 2017
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 4,189	$ 3,841
Accumulated Amortization	(3,342)	(3,072)
Net Carrying Amount	$ 847	$ 769
Weighted Average Remaining Useful Life	17 years 1 month 6 days	17 years 10 months 24 days
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,637	$ 2,458
Accumulated Amortization	(2,637)	(2,458)
Brands Associated with Acquired Cell Lines [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	544	507
Accumulated Amortization	(137)	(121)
Net Carrying Amount	$ 407	$ 386
Weighted Average Remaining Useful Life	29 years 10 months 24 days	30 years 4 months 24 days
Product Licenses [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 837	$ 716
Accumulated Amortization	(397)	(333)
Net Carrying Amount	$ 440	$ 383
Weighted Average Remaining Useful Life	5 years 3 months 18 days	5 years 4 months 24 days
Other Intangibles [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 171	$ 160
Accumulated Amortization	$ (171)	$ (160)