Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets
Marketable securities - corporate bonds and mutual funds	$ 4,735	$ 6,025
Investment in Hoth	1,020
Liabilities
Fair value of warrant liabilities	961	702
Quoted prices in active markets (Level 1) [Member]
Assets
Marketable securities - corporate bonds and mutual funds		211
Significant other observable inputs (Level 2) [Member]
Assets
Marketable securities - corporate bonds and mutual funds	4,735	5,814
Significant unobservable inputs (Level 3) [Member]
Assets
Marketable securities - corporate bonds and mutual funds
Investment in Hoth	1,020
Liabilities
Fair value of warrant liabilities	$ 961	$ 702