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NanoTx License Agreement - Additional Information (Details) - USD ($) | May 07, 2020 | Dec. 31, 2020 | Dec. 31, 2019
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Common stock, shares issued (in shares) |  | 6,749,028 | 3,880,588
Common stock, $0.001 par value; 100,000,000 shares authorized; 6,749,028 and 3,880,588 shares issued and outstanding in 2020 and 2019, respectively |  | $ 7,000 | $ 4,000
Nano Tx Licenses Agreement [Member] |  |  |
License fee payment in cash | $ 400,000 |  |
Common stock, shares issued (in shares) | 230,769 |  |
Common stock, $0.001 par value; 100,000,000 shares authorized; 6,749,028 and 3,880,588 shares issued and outstanding in 2020 and 2019, respectively | $ 781,000 |  |
Nano Tx Licenses Agreement [Member] | Development And Sales Milestone [Member] |  |  |
Milestone payments | $ 136,500,000 |  |

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- Definition The amount of cash paid for royalties during the current period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3536-108585 + Details
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