Intangible Assets and Goodwill Amortization expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangibles	$ 943	$ 1,212	$ 1,928
Cost of revenues
Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangibles	286	455	1,024
Operating expenses
Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangibles	$ 657	$ 757	$ 904