Discontinued Operations - Additional Information (Details) - USD ($)		9 Months Ended
	Jan. 05, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Common stock investment		$ 13,089,000		$ 0
Amounts reclassified from accumulated other comprehensive income		1,183,000	$ 0
Infectious Disease Business | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total sale price	$ 166,400,000
Consideration received (in shares)	3,313,702
Consideration received, market value	$ 54,500,000
Receivable due in 12 months	25,000,000
Receivable due in 18 months	25,000,000
Fair value of payments	45,900,000
Contingent payments	$ 246,200,000
Disposition related costs		$ 11,900,000
Minimum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Excess cash payments over fair value, amortization period		12 months
Minimum | Infectious Disease Business | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Tiered royalty payments, percent of net sales	5.00%
Maximum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Excess cash payments over fair value, amortization period		18 months
Maximum | Infectious Disease Business | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Tiered royalty payments, percent of net sales	25.00%
Prepaid Expenses and Other Current Assets | Infectious Disease Business | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fair value of payments	$ 23,300,000
Other Assets | Infectious Disease Business | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fair value of payments	$ 22,600,000	$ 48,700,000
Melinta
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Common stock investment		$ 13,100,000