Description of Business and Summary of Significant Accounting Policies (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Assets [Abstract]
Total assets measured at fair value	[1]	$ 21,438	$ 31,873
Liabilities [Abstract]
Total liabilities measured at fair value	[1]	12,466	24,976
Fair Value, Inputs, Level 1 [Member]
Assets [Abstract]
Total assets measured at fair value	[1]	21,438	31,873
Fair Value, Inputs, Level 2 [Member]
Liabilities [Abstract]
Total liabilities measured at fair value	[1]	0	0
Fair Value, Inputs, Level 3 [Member]
Liabilities [Abstract]
Total liabilities measured at fair value	[1]	12,466	24,976
Contingent accrued earn-out acquisition consideration [Member]
Liabilities [Abstract]
Derivative liabilities	[1],[2]	12,466	24,976
Contingent accrued earn-out acquisition consideration [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities [Abstract]
Derivative liabilities	[1],[2]	12,466	24,976
Certificates of Deposit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities		19,086	26,714
Certificates of Deposit [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities		19,086	26,714
Mutual Fund [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities		2,352	5,159
Mutual Fund [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities		2,352	5,159
Certificates of Deposit [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities		520	680
Mutual Fund [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities		$ 2,352	$ 5,159

[1] months ended March 31, 2019 and the year ended December 31, 2018 there were no transfers between fair value levels 1, 2, or 3.

[2] The income valuation approach is applied and the valuation inputs include the contingent payment arrangement terms, projected cash flows, rate of return, and probability assessments.