Goodwill and Acquired Intangible Assets (Acquired Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 19,935	$ 19,810
Accumulated amortization	(9,431)	(7,472)
Net carrying amount	10,504	12,338
Indefinite-lived Intangible Assets Acquired	1,945	1,912
Intellectual Property [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	16,584	16,509
Accumulated amortization	(8,044)	(6,147)
Net carrying amount	$ 8,540	$ 10,362
Intellectual Property [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)	7 years	7 years
Intellectual Property [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)	15 years	15 years
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)	4 years 6 months	4 years 6 months
Gross carrying amount	$ 834	$ 820
Accumulated amortization	(834)	(820)
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	572	569
Accumulated amortization	(553)	(505)
Net carrying amount	$ 19	$ 64
Other [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)	2 years	2 years
Other [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization period (years)	6 years	6 years