Percentage of Accounts Receivable by Significant Customers (Detail) - Customer Concentration Risk - Accounts Receivable	6 Months Ended	12 Months Ended
Jun. 30, 2018	Dec. 31, 2017
GE Healthcare
Concentration Risk [Line Items]
Accounts receivable, percentage by customer	17.00%	11.00%
MilliporeSigma
Concentration Risk [Line Items]
Accounts receivable, percentage by customer	14.00%	19.00%

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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