Fair Value Measurements (Fair Value, Warrants Measured on Recurring Basis) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Fair value of warrants at beginning of period	$ 271
Unrealized (loss) gain on fair value adjustment for warrants	231	$ (1)
Fair value of warrants at end of period	40
Level 3 Estimated Fair Value [Member]
Fair value of warrants at beginning of period	271	229
Unrealized (loss) gain on fair value adjustment for warrants	(231)	1
Fair value of warrants at end of period	$ 40	$ 230