Fair Value Measurements (Details 5) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Financial Assets
Cash and cash equivalents	$ 21,451	$ 30,557	$ 40,514	$ 32,182
Cash and cash equivalents at fair value	21,451	30,557
Finance receivables	165,843	151,995
Finance receivables at fair value	165,843	151,995
Marketable investments	1,713	1,856
Marketable investments at fair value	1,713	1,856
Warrant assets	1,519	987
Warrant assets at fair value	1,519	987
Financial Liabilities
Warrant liability	65	91
Gross liability at fair value	65	91
Fair Value, Inputs, Level 1 [Member]
Financial Assets
Cash and cash equivalents at fair value	21,451	30,557
Marketable investments at fair value	1,132	1,256
Fair Value, Inputs, Level 3 [Member]
Financial Assets
Cash and cash equivalents
Finance receivables at fair value	165,843	151,995
Marketable investments at fair value	581	600
Warrant assets at fair value	1,519	987
Financial Liabilities
Gross liability at fair value	$ 65	$ 91