The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Note 5 - Goodwill and Other Intangible Assets (Details Textual) $ in Thousands, € in Millions			3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 22, 2021 USD ($)	Jan. 22, 2021 EUR (€)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Goodwill, Acquired During Period					$ 281,845
Finite Lived Intangible Assets, Foreign Currency Translation Gain (Loss)							$ 0
Amortization of Intangible Assets, Total			$ 1,600	$ 800	4,600	$ 2,300
Acquired 3D Hubs [Member]
Goodwill, Acquired During Period					281,800
Finite-lived Intangible Assets Acquired					30,800
Finite Lived Intangible Assets, Foreign Currency Translation Gain (Loss)					$ (700)
Acquired 3D Hubs [Member] \| Europe [Member]
Goodwill, Acquired During Period \| €		€ 106.5
Finite-lived Intangible Assets Acquired \| €		€ 11.6
Acquired 3D Hubs [Member] \| UNITED STATES
Goodwill, Acquired During Period	$ 152,200
Finite-lived Intangible Assets Acquired	$ 16,600