Segment Reporting - Percentage of Accounts Receivable by Significant Customers (Detail) - Accounts Receivable	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Concentration Risk [Line Items]
Accounts receivable, percentage by customer	10.00%
Customer Concentration Risk \| GE Healthcare
Concentration Risk [Line Items]
Accounts receivable, percentage by customer	15.00%	17.00%
Customer Concentration Risk \| MilliporeSigma
Concentration Risk [Line Items]
Accounts receivable, percentage by customer	0.00%	11.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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