Accounts Receivable (Details) - USD ($)			3 Months Ended		12 Months Ended
	Mar. 01, 2018	Dec. 13, 2016	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2017	Feb. 28, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of counterparty payable offset by guarantor						50.00%
Royalty guarantees commitments amount						$ 6,250,000
Accounts receivable			$ 1,649,000				$ 11,697,000
License fees			$ 5,625,000	$ 0
SWK Purchase Agreement
Accounts, Notes, Loans and Financing Receivable [Line Items]
Upfront purchase price received under purchase agreement		$ 13,750,000
Legal fees		40,000
Milestone payment receivable under purchase agreement		3,750,000
Percent of milestone payments due							90.00%
Accounts receivable	$ 5,600,000						$ 11,697,000
Proceeds From milestone payments	$ 6,100,000
Minimum | SWK Purchase Agreement
Accounts, Notes, Loans and Financing Receivable [Line Items]
Milestone amount, achieved in two consecutive fiscal quarters					$ 25,000,000
SWK Funding LLC | SWK Purchase Agreement
Accounts, Notes, Loans and Financing Receivable [Line Items]
Royalty and licensing revenue		$ 26,250,000
Percent received upon milestone payment		10.00%
Milestone period		6 years
Percent received upon milestone payment, without commercialization		5.00%
Percent received without milestone payment		7.86%
Percent received without milestone payment, without commercialization		3.93%
Percent of milestone payments due							10.00%
SWK Funding LLC | Maximum | SWK Purchase Agreement
Accounts, Notes, Loans and Financing Receivable [Line Items]
Royalty and licensing revenue		$ 20,625,000