Share-Based Compensation - Outstanding and exercisable options (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Outstanding and exercisable options, weighted average exercise price
Weighted average remaining contractual life (in years)	6 years 10 months 24 days	6 years 10 months 24 days
Weighted average remaining contractual life for vested options (in years)	5 years 6 months	6 years
Unrecognized compensation cost	$ 7.3	$ 7.4
Expected period for recognition	2 years 11 months 19 days	2 years 1 month 2 days
Plans 2011 and 2019 and 2021 Inducement
Outstanding and exercisable options, number of shares
Outstanding at end of year	13,146,497	11,128,491
Exercisable at end of year	8,034,214	7,777,923
Outstanding and exercisable options, weighted average exercise price
Outstanding at end of year	$ 3.6	$ 4.22
Exercisable at end of year	$ 4.61	$ 4.85
2011 Plan
Outstanding and exercisable options, number of shares
Outstanding at beginning of year	1,294,691	1,632,485
Outstanding at end of year	1,294,691	1,632,485
Exercisable at end of year	1,294,691	1,632,485
Outstanding and exercisable options, weighted average exercise price
Outstanding at beginning of year	$ 2.23	$ 2.11
Outstanding at end of year	2.23	2.11
Exercisable at end of year	$ 2.23	$ 2.11
2019 Plan
Outstanding and exercisable options, number of shares
Outstanding at beginning of year	8,591,306	7,604,606
Granted	2,131,500	1,151,400
Cancelled	(561,000)
Outstanding at end of year	10,722,806	8,756,006
Exercisable at end of year	6,260,668	5,795,146
Outstanding and exercisable options, weighted average exercise price
Outstanding at beginning of year	$ 4.21	$ 4.97
Granted	1.95	2.02
Outstanding at end of year	3.76	4.58
Exercisable at end of year	$ 4.99	$ 5.54
Inducement Plan
Outstanding and exercisable options, number of shares
Outstanding at beginning of year	710,000	496,000
Granted	419,000	244,000
Outstanding at end of year	1,129,000	740,000
Exercisable at end of year	478,855	350,292
Outstanding and exercisable options, weighted average exercise price
Outstanding at beginning of year	$ 4.76	$ 5.99
Granted	1.96	2.01
Outstanding at end of year	3.72	4.68
Exercisable at end of year	$ 5.99	$ 6.22

The number of shares under options that were cancelled during the reporting period pertaining to the stock option plan.

No definition available.

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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- Definition

Gross number of share options (or share units) granted during the period.

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- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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-Topic 718
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-Paragraph 2
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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- Definition

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Subparagraph (e)(1)
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- Definition

Weighted average remaining contractual term for fully vested and expected to vest exercisable or convertible options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

+ References

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-Topic 718
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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