Segment Reporting - (Summary of Product Revenues by Product Line) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue from External Customer [Line Items]
Revenue	$ 60,634	$ 44,830
Increase decrease In Revenue From Contract With Customer	$ 15,813
Percentage Of Incraese decrease In Revenue From Contract With Customer	35.30%
Chromatography products
Revenue from External Customer [Line Items]
Revenue	$ 13,890	10,583
Increase decrease In Revenue From Contract With Customer	$ 3,307
Percentage Of Incraese decrease In Revenue From Contract With Customer	31.20%
Filtration products
Revenue from External Customer [Line Items]
Revenue	$ 28,882	19,793
Increase decrease In Revenue From Contract With Customer	$ 9,089
Percentage Of Incraese decrease In Revenue From Contract With Customer	45.90%
Protein products
Revenue from External Customer [Line Items]
Revenue	$ 16,653	13,586
Increase decrease In Revenue From Contract With Customer	$ 3,067
Percentage Of Incraese decrease In Revenue From Contract With Customer	22.60%
Other
Revenue from External Customer [Line Items]
Revenue	$ 1,187	$ 837
Increase decrease In Revenue From Contract With Customer	$ 350
Percentage Of Incraese decrease In Revenue From Contract With Customer	41.80%