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Note 10 - Net Loss Per Share - Anti-dilutive Securities (Details) - shares shares in Thousands | 3 Months Ended | 6 Months Ended
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Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021
Potentially dilutive common shares (in shares) |  | 57,262 | 43,639 | 55,370 | 31,226
Unvested Stock [Member] |  |  |  |  |
Potentially dilutive common shares (in shares) |  | 1,981 | 1,555 | 1,666 | 1,034
Convertible Preferred Stocks [Member] |  |  |  |  |
Potentially dilutive common shares (in shares) |  | 41,725 | 27,129 | 40,159 | 16,143
Common Stock Warrants [Member] |  |  |  |  |
Potentially dilutive common shares (in shares) |  | 1,474 | 2,873 | 1,463 | 1,967
IPO Warrants [Member] |  |  |  |  |
Potentially dilutive common shares (in shares) | [1] | 12,082 | 12,082 | 12,082 | 12,082
[1] | The IPO Warrants were issued in connection with our initial public offering in 2015. The IPO Warrants are exercisable at a price of $11.50 per share and expire on July 24, 2022. The Company may redeem the IPO Warrants at a price of $0.01 per IPO Warrant upon 30 days’ notice only if the last sale price of our common stock is at least $17.50 per share for any 20 trading days within a 30 trading day period. If the Company redeems the IPO Warrants in this manner, the Company will have the option to do so on a cashless basis with the issuance of an economically equivalent number of shares of Company common stock.

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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI https://asc.fasb.org/extlink&oid=124432515&loc=d3e3550-109257 + Details
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