Credit Facilities (Various credit facilities) (Details)					9 Months Ended
	Jan. 12, 2018 USD ($)	Apr. 03, 2017 USD ($) $ / shares shares	Jul. 29, 2016 USD ($)	Jul. 21, 2015 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Jul. 31, 2016 USD ($)	Mar. 31, 2016 USD ($)
Revolving Credit Facility | Bank of America
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				$ 20,000,000.0
Debt instrument, term				2 years
Debt instrument, termination notice period				3 days
Debt covenant, minimum current ratio				1.5
Revolving Credit Facility | MidCap Financial Trust
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity			$ 50,000,000.0
Deferred financing costs			$ 900,000					$ 900,000
Debt issuance costs						$ 800,000
Restricted cash							$ 2,000,000.0
Revolving Credit Facility | MidCap Financial Trust | London Interbank Offered Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate			4.10%
Variable rate, maximum			0.50%
Revolving Credit Facility | Deerfield ELGX Revolver, LLC
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		$ 50,000,000
Amount borrowed					$ 21,000
Restricted cash					2,000,000.0
Deferred financing costs					$ 1,000,000
Debt issuance costs, gross		$ 1,200,000
Revolving Credit Facility | Deerfield ELGX Revolver, LLC | London Interbank Offered Rate
Line of Credit Facility [Line Items]
Debt instrument, floor		1.00%
Basis spread on variable rate		4.60%
Revolving Credit Facility | Minimum | Bank of America
Line of Credit Facility [Line Items]
Liquidation proceeds, credit derivative (not less than)				$ 30,000,000.0
Letter of Credit | Bank of America
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				$ 10,000,000.0
Secured Debt | Facility Agreement, Due 2023
Line of Credit Facility [Line Items]
Convertible notes, stated percentage					6.87%
Convertible notes, face amount		$ 120,000,000
Deferred financing costs		5,100,000			$ 4,500,000
Periodic payment		$ 40,000,000
Long-term debt					106,500,000
Secured Debt | Facility Agreement, Due 2023 | Minimum
Line of Credit Facility [Line Items]
Periodic payment, interest					1,500,000
Secured Debt | Facility Agreement, Due 2023 | Maximum
Line of Credit Facility [Line Items]
Periodic payment, interest					$ 12,700,000
Facility Agreement, Due 2023, Deerfield Warrants | Facility Agreement, Due 2023
Line of Credit Facility [Line Items]
Expiration date					7 years
Exercise limitation threshold					4.985%
Facility Agreement, Due 2023, Deerfield Warrants | Common Stock | Facility Agreement, Due 2023
Line of Credit Facility [Line Items]
Number of securities called by warrants | shares		6,470,000
Exercise price of warrants or rights (usd per share) | $ / shares		$ 9.23
Warrants and rights outstanding (in shares)		$ 14,300,000
Debt issuance costs, gross		$ 400,000
Subsequent Event | Revolving Credit Facility | Deerfield ELGX Revolver, LLC
Line of Credit Facility [Line Items]
Termination fee	$ 1,300,000