Fair Value Measurement and Fair Value of Financial Instruments (Reconciliation of Assets and Liabilities Measured on Recurring Basis) (Details) - Fair Value, Measurements, Recurring - Significant Unobservable Inputs (Level 3) - Equity warrants $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	$ 679
Included in earnings	244
Issuances	8
Ending balance	$ 931