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Stockholders' Equity - Additional Information (Detail) - $ / shares | Dec. 31, 2020 | Sep. 30, 2020
--- | --- | ---
Class Of Stock [Line Items] |  |
Capital stock authorized for issuance | 150,000,000 |
Common stock, shares authorized | 145,000,000 | 145,000,000
Common stock, par value | $ 0.001 | $ 0.001
Preferred stock, shares authorized | 5,000,000 |
Preferred stock, par value | $ 0.001 |
Common stock, shares outstanding | 103,194,240 | 102,376,000
2004 Equity Incentive Plan, 2013 Equity Incentive Plan, and Inducement Grants |  |
Class Of Stock [Line Items] |  |
Common Stock, Share reserve for issuance | 7,635,023 |

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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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