Note 8 - Operating Leases (Details Textual)	Dec. 31, 2019 ft²
Operating Lease, Weighted Average Discount Rate, Percent	4.10%
Operating Lease, Weighted Average Remaining Lease Term	16 years 292 days
Administrative, Research and Development, and Manufacturing Space in Bedford, MA [Member]
Area of Real Estate Property	134,000
Office, Research and Development, Training, and Warehousing Space in Padova, Italy [Member]
Area of Real Estate Property	33,000

Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (g)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant