Reportable Segments and Major Concentration Data - Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Net revenues	$ 50,846	$ 48,440	$ 50,248	$ 51,480	$ 53,100	$ 51,737	$ 56,451	$ 52,283	$ 201,014	$ 213,571	$ 200,771
Operating income									32,699	31,584	37,382
Depreciation and amortization									9,964	8,688	9,090
Capital expenditures									3,797	4,201	4,467
Goodwill	89,241				54,637				89,241	54,637	54,926
Other intangible assets	60,243				23,113				60,243	23,113	26,704
Total assets	325,478				251,377				325,478	251,377	249,777
Restructuring and litigation costs									2,596	7,779	762
Diagnostics [Member]
Segment Reporting Information [Line Items]
Net revenues									136,682	150,454	143,521
Life Science [Member]
Segment Reporting Information [Line Items]
Net revenues									64,332	63,117	57,250
Corporate [Member]
Segment Reporting Information [Line Items]
Operating income									(10,373)	(15,076)	(11,097)
Eliminations [Member]
Segment Reporting Information [Line Items]
Operating income									101	292	269
Total assets	(83)				58				(83)	58
Net revenues									(823)	(789)	(926)
Operating Segments [Member] | Diagnostics [Member]
Segment Reporting Information [Line Items]
Net revenues									136,682	150,454	143,521
Operating income									22,399	32,569	34,124
Depreciation and amortization									7,676	6,557	7,037
Capital expenditures									2,049	2,477	2,554
Goodwill	70,395				35,213				70,395	35,213	35,213
Other intangible assets	59,807				22,068				59,807	22,068	24,973
Total assets	255,169				180,978				255,169	180,978	180,226
Net revenues									462	392	389
Operating Segments [Member] | Life Science [Member]
Segment Reporting Information [Line Items]
Net revenues									64,332	63,117	57,250
Operating income									20,572	13,799	14,086
Depreciation and amortization									2,288	2,131	2,053
Capital expenditures									1,748	1,724	1,913
Goodwill	18,846				19,424				18,846	19,424	19,713
Other intangible assets	436				1,045				436	1,045	1,731
Total assets	$ 70,392				$ 70,341				70,392	70,341	69,938
Net revenues									$ 361	$ 397	537
Operating Segments [Member] | Eliminations [Member]
Segment Reporting Information [Line Items]
Total assets											$ (387)