Note 11 - Revenue and Geographic Information - Total Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Injection Molding (Protomold) [Member]
Revenue:
Revenues	$ 46,445	$ 41,971	$ 134,376	$ 119,521
CNC Machining (Firstcut) [Member]
Revenue:
Revenues	21,781	19,833	60,510	54,788
3D Printing (Fineline) [Member]
Revenue:
Revenues	9,850	6,038	28,059	16,038
Other Products [Member]
Revenue:
Revenues	97		2,757
Revenues	$ 78,173	$ 67,842	$ 225,702	$ 190,347