Sales of Certain International Segment Assets - Additional Information (Detail) $ in Thousands, AUD in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 AUD	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Assets Of Disposal Group Including Discontinued Operation [Line Items]
Gain on sale of assets		$ 0		$ 6,385	$ 0
Canadian Radiopharmacies and Gludef Manufacturing and Distribution Business
Assets Of Disposal Group Including Discontinued Operation [Line Items]
Purchase price for asset sale	$ 9,000
Working capital adjustment	$ 500
Gain on sale of assets				5,900
Australian Radiopharmacy Servicing Subsidiary
Assets Of Disposal Group Including Discontinued Operation [Line Items]
Gain on sale of assets				500
Share sale price			AUD 2.0	1,500
Working capital adjustment in sale of stock units			2.0	1,500
Gross proceeds from sale of stock units			AUD 4.0	3,000
Net proceeds from sale of stock units				2,200
Working Capital Assets Liabilities Sold				2,000
Reclassification from other comprehensive income to gain on sales of assets				$ (400)