Note 1 - The Company and Basis of Presentation (Details Textual) - USD ($)
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1 Months Ended |
2 Months Ended |
3 Months Ended |
9 Months Ended |
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Jul. 02, 2021 |
May 04, 2021 |
Jan. 19, 2021 |
Jun. 09, 2020 |
Jun. 08, 2020 |
Apr. 20, 2020 |
Apr. 16, 2020 |
Feb. 28, 2021 |
Feb. 29, 2020 |
Mar. 31, 2021 |
Sep. 30, 2021 |
Sep. 30, 2020 |
Sep. 30, 2021 |
Sep. 30, 2020 |
May 03, 2021 |
Jan. 31, 2021 |
Jan. 18, 2021 |
Dec. 31, 2020 |
Dec. 16, 2020 |
Dec. 15, 2020 |
Apr. 15, 2020 |
Dec. 31, 2019 |
Fair Value Adjustment of Warrants |
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$ (0)
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$ (0)
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$ 373,000
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$ 1,838,000
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Proceeds from Warrant Exercises |
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$ 179,000
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8,407,000
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Preferred Stock, Shares Authorized (in shares) |
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10,000,000
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10,000,000
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10,000,000
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[1] |
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Proceeds from Issuance of Common Stock |
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$ 25,122,000
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0
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Payments of Warrant Issuance Costs |
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$ 326,000
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(0)
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333,000
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Retained Earnings (Accumulated Deficit), Ending Balance |
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$ (235,525,000)
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(235,525,000)
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$ (219,826,000)
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[1] |
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Net Cash Provided by (Used in) Operating Activities, Total |
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(9,651,000)
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(12,936,000)
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Net Cash Provided by (Used in) Financing Activities, Total |
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25,955,000
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9,231,000
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Proceeds from Stock Plans |
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21,000
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$ 0
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Cash and Cash Equivalents, at Carrying Value, Ending Balance |
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22,665,000
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22,665,000
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$ 6,523,000
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[1] |
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Working Capital |
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$ 23,563,000
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$ 23,563,000
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Series C Preferred Stock [Member] |
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Convertible Preferred Stock, Shares Issued upon Conversion (in shares) |
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1
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1
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Preferred Stock, Shares Outstanding, Ending Balance (in shares) |
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0
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0
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0
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0
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Preferred Stock, Par or Stated Value Per Share (in dollars per share) |
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$ 0.0001
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$ 0.0001
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$ 0.0001
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Series A Preferred Stock [Member] |
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Convertible Preferred Stock, Shares Issued upon Conversion (in shares) |
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1
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1
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Preferred Stock, Shares Outstanding, Ending Balance (in shares) |
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0
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0
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0
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Preferred Stock, Shares Authorized (in shares) |
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547,345
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Preferred Stock, Par or Stated Value Per Share (in dollars per share) |
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$ 0.0001
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Series B, A-2 and B-2 Common Stock Warrants [Member] |
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Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) |
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$ 2.817
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$ 3.40
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Fair Value Adjustment of Warrants |
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$ 86,000
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Warrants Issued in Connection with Class A Units [Member] | Class A Units [Member] |
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Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) |
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$ 3.40
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Warrants Per Unit (in shares) |
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1
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Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) |
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1
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Warrants and Rights Outstanding, Term (Year) |
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5 years
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Warrants Issued in Connection with Class B Units [Member] | Class B Units [Member] |
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Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) |
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$ 3.40
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Warrants Per Unit (in shares) |
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1
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Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) |
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1
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Warrants and Rights Outstanding, Term (Year) |
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5 years
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Warrants Issued in Connection with January 2021 Offering [Member] |
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Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) |
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$ 3.40
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Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) |
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1
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Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) |
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8,117,640
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8,104,880
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8,104,880
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8,104,880
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8,117,640
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Stock Issued During Period, Shares, Warrant Exercises (in shares) |
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12,760
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Proceeds from Warrant Exercises |
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$ 43,000
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Series A and Series B Warrants [Member] |
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Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) |
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$ 3.40
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$ 6.10
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$ 15.50
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Proceeds from Warrant Exercises |
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$ 3,089,000
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Series B Warrants [Member] |
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Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) |
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3.40
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$ 6.10
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Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) |
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285,632
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285,632
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Stock Issued During Period, Shares, Warrant Exercises (in shares) |
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24,279
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40,000
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4,548
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Proceeds from Warrant Exercises |
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$ 136,000
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$ 70,000
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Series A-2 and Series B-2 Warrants [Member] |
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Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) |
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$ 3.40
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$ 6.371
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$ 6.371
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Fair Value Adjustment of Warrants |
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$ 287,000
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Warrants and Rights Outstanding, Term (Year) |
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5 years
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Series A Warrants [Member] |
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Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) |
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0
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0
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Stock Issued During Period, Shares, Warrant Exercises (in shares) |
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482,059
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102,626
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Proceeds from Warrant Exercises |
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$ 1,591,000
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Series A-2 Warrants [Member] |
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Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) |
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482,059
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392,830
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392,830
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Stock Issued During Period, Shares, Warrant Exercises (in shares) |
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392,830
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Series B-2 Warrants [Member] |
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Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) |
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24,279
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20,380
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20,380
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Stock Issued During Period, Shares, Warrant Exercises (in shares) |
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20,380
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Universal Shelf Registration Statement [Member] |
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Universal Shelf Registration Statement, Proposed Maximum Securities Offering |
$ 75,000,000
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Universal Shelf Registration Statement, Maximum Capacity |
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$ 75,000,000
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$ 75,000,000
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Stock Issued During Period, Shares, New Issues (in shares) |
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0
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Proceeds from Issuance or Sale of Equity, Total |
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$ 0
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Purchase Agreement with LPC [Member] |
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Stock Issued During Period, Shares, New Issues (in shares) |
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250,000
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52,500
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Shares Issued, Price Per Share (in dollars per share) |
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$ 2.817
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$ 6.50
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Maximum Amount of Shares Issuable |
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$ 10,000,000
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Stock Purchase Agreement Duration Period (Month) |
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30 months
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Stock Purchase Agreement, Maximum Issuable Shares (in shares) |
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301,762
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Stock Purchase Agreement, Maximum Issuable Shares, Percent of Outstanding Stock |
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19.99%
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Stock Purchase Agreement, Share Price Covenant Trigger (in dollars per share) |
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$ 6.46
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Proceeds from Issuance of Common Stock |
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$ 704,000
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$ 341,000
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Equity Facility, Remaining Financing Commitment |
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$ 9,000,000
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9,000,000
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Proceeds From Issuance of Common Stock, Net |
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633,000
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January 2021 Offering [Member] |
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Shares Issued, Price Per Share (in dollars per share) |
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$ 3.40
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Proceeds from Issuance or Sale of Equity, Total |
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$ 27,600,000
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Proceeds from Issuance or Sale of Equity, Net of Issuance Costs |
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$ 25,122,000
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Proceeds From Issuance of Common Stock, Net |
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|
|
|
|
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|
$ 25,122,000
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January 2021 Offering [Member] | Class A Units [Member] |
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Shares Issued, Price Per Share (in dollars per share) |
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$ 3.40
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Units Issued, Shares (in shares) |
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4,607,940
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Common Shares Per Unit (in shares) |
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1
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Warrants Per Unit (in shares) |
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1
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January 2021 Offering [Member] | Class B Units [Member] |
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Shares Issued, Price Per Share (in dollars per share) |
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$ 3.40
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Units Issued, Shares (in shares) |
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2,450,880
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Common Shares Per Unit (in shares) |
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1
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Warrants Per Unit (in shares) |
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1
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Series C Convertible Preferred Stock Per Unit (in shares) |
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1
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January 2021 Offering [Member] | Series C Preferred Stock [Member] |
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Stock Issued During Period, Shares, New Issues (in shares) |
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2,450,880
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Convertible Preferred Stock, Shares Issued upon Conversion (in shares) |
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1
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1
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Over-Allotment Option [Member] |
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Stock Issued During Period, Shares, New Issues (in shares) |
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1,058,820
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Over-Allotment Option [Member] | Warrants Issued in Connection with January 2021 Offering [Member] |
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Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) |
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1,058,820
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First Amendment to the LPC Purchase Agreement [Member] |
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Stock Issued During Period, Shares, New Issues (in shares) |
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250,000
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Shares Issued, Price Per Share (in dollars per share) |
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$ 2.817
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Stock Purchase Agreement, Maximum Issuable Shares (in shares) |
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2,068,342
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Stock Purchase Agreement, Maximum Issuable Shares, Percent of Outstanding Stock |
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19.99%
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Stock Purchase Agreement, Share Price Covenant Trigger (in dollars per share) |
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$ 2.99
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Proceeds from Issuance of Common Stock |
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$ 704,000
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