Note 3 - Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue:
Revenue	$ 458,728	$ 445,596	$ 344,490
Injection Molding (Protomold) [Member]
Revenue:
Revenue	217,415	210,523	194,432
CNC Machining (Firstcut) [Member]
Revenue:
Revenue	155,473	153,521	103,739
3D Printing (Fineline) [Member]
Revenue:
Revenue	61,352	53,342	43,329
Sheet Metal [Member]
Revenue:
Revenue	21,000	24,998	1,767
Other Products [Member]
Revenue:
Revenue	3,488	3,212	1,223
UNITED STATES
Revenue:
Revenue	360,205	350,535	263,086
Europe [Member]
Revenue:
Revenue	82,805	80,889	70,154
JAPAN
Revenue:
Revenue	$ 15,718	$ 14,172	$ 11,250

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration