Fair Value of Financial Assets and Liabilitiest (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Assets
Marketable securities - corporate bonds and mutual funds	$ 2,920	$ 6,025
Fair value of investment	675
Liabilities
Fair value of warrant liabilities	2,028	$ 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	2,920		5,814
Significant unobservable inputs (Level 3) [Member]
Assets
Marketable securities - corporate bonds and mutual funds
Fair value of investment	675
Liabilities
Fair value of warrant liabilities	$ 2,028		$ 702