Note 5 - Common Shares (Details Textual) - shares	Dec. 31, 2020	Dec. 31, 2019
Common Stock, Shares, Issued, Total (in shares)	25,639,702	25,053,480
Common Stock, Shares, Outstanding, Ending Balance (in shares)	25,228,951	24,592,578
Reserved For Issuance Upon Exercise Or Vesting Of Equity Awards [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)	5,600,676
Reserved For Issuance Upon Exercise Or Vesting Of Equity Awards [Member] \| Share-based Payment Arrangement, Option [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)	484,500
NIL Coupon Non-redeemable Convertible Unsecured Loan Notes [Member] \| Unsecured Debt [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)	6,715

Aggregate number of common shares reserved for future issuance.

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-Topic 210
-SubTopic 10
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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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