Discontinued Operations - Additional Information (Detail) - Horizon Clinicals and Series2000 [Member]	12 Months Ended
Dec. 31, 2018 USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (Loss) on disposal of discontinued operations before tax	$ 0
Accrued expenses	$ 900,000

Amount classified as accrued liabilities attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.

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