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v3.20.1

Subsequent Events - Additional Information (Details) - USD ($) |  |  |  |  | 3 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
May 07, 2020 | Apr. 23, 2020 | Apr. 01, 2020 | Mar. 29, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Mar. 31, 2019 | Apr. 30, 2020 | Dec. 31, 2019 | Aug. 06, 2019 | Aug. 05, 2019 | May 29, 2015
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Warrant liability |  |  |  |  |  | $ 5,262,000 |  |  | $ 6,929,000 |  |  |
Change in fair value of warrants |  |  |  |  |  | $ (1,667,000) | $ (210,000) |  |  |  |  |
Common stock, shares issued (in shares) |  |  |  |  |  | 3,880,588 |  |  | 3,880,588 | 50,000,000 | 50,000,000 |
NanoTx License Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
License fee payment in cash |  |  |  | $ 400,000 |  |  |  |  |  |  |  |
Term Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of shares callable by warrants (in shares) |  |  |  |  |  |  |  |  |  |  |  | 188
Warrant exercise price (in dollars per share) |  |  |  |  |  |  |  |  |  |  |  | $ 5,175
Scenario Forecast [Member] |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Change in fair value of warrants |  |  |  |  | $ 700,000 |  |  |  |  |  |  |
Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Warrant liability |  |  |  |  |  |  |  | $ 4,200,000 |  |  |  |
Subsequent Event [Member] | NanoTx License Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
License agreement expiration date | May 07, 2020 |  |  |  |  |  |  |  |  |  |  |
License fee payment in cash | $ 400,000 |  |  |  |  |  |  |  |  |  |  |
Common stock, shares issued (in shares) | 230,769 |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Member] | Term Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Repayment of debt |  |  | $ 5,000,000 |  |  |  |  |  |  |  |  |
Final payment fee |  |  | $ 308,000 |  |  |  |  |  |  |  |  |
Subsequent Event [Member] | Revised Warrant Agreements [Member] | Series T Warrants [Member] |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of shares callable by warrants (in shares) |  | 1 |  |  |  |  |  |  |  |  |  |
Series U Warrants [Member] | Subsequent Event [Member] | Revised Warrant Agreements [Member] |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of warrants |  | 3,372,000 |  |  |  |  |  |  |  |  |  |
Warrant exercise price decrease |  | $ 2.25 |  |  |  |  |  |  |  |  |  |
Outstanding Warrants [Member] | Subsequent Event [Member] | Revised Warrant Agreements [Member] | Series T Warrants [Member] |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of shares callable by warrants (in shares) |  | 50 |  |  |  |  |  |  |  |  |  |
Warrant exercise price (in dollars per share) |  | $ 2.25 |  |  |  |  |  |  |  |  |  |

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