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The Company and its Significant Accounting Policies - Additional Information (Details) $ / shares in Units, $ in Thousands |  |  |  | 3 Months Ended | 9 Months Ended |
--- | --- | --- | --- | --- | --- | ---
May 22, 2019 USD ($) $ / shares shares | May 14, 2019 $ / shares shares | Nov. 02, 2018 | Jun. 30, 2020 USD ($) | Sep. 30, 2019 USD ($) | Sep. 30, 2019 USD ($) Employee shares | Sep. 30, 2018 USD ($) | Dec. 31, 2018 USD ($)
Company And Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Reverse stock split ratio |  |  | 0.0667 |  |  |  |  |
Cash and cash equivalents |  |  |  |  | $ 16,349 | $ 16,349 |  | $ 13,049
Net proceeds from issuance of IPO |  |  |  |  |  | 37,180 |  |
Cash and investment for operating activities |  |  |  |  |  | $ 28,803 | $ 1,987 |
Number of employees reduced related to restructuring activities | Employee |  |  |  |  |  | 14 |  |
Aggregate restructuring charges |  |  |  |  | 578 | $ 578 |  |
Restructuring charges paid |  |  |  |  | 128 |  |  |
IPO closing date |  | May 14, 2019 |  |  |  |  |  |
Unpaid issuance cost and charged to accounts payable or accrued expenses |  |  |  |  | 331 | $ 331 |  |
Forecast |  |  |  |  |  |  |  |
Company And Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Aggregate restructuring charges |  |  |  | $ 450 |  |  |  |
Common Stock |  |  |  |  |  |  |  |
Company And Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Shares issued and sold | shares |  |  |  |  |  | 227,628 |  |
Common Stock | IPO |  |  |  |  |  |  |  |
Company And Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Net proceeds from issuance of IPO | $ 36,849 |  |  |  |  | $ 36,849 |  |
Shares issued and sold | shares | 505,714 | 3,571,429 |  |  |  | 4,297,901 |  |
Shares issued and sold, price per share | $ / shares | $ 11.00 | $ 11.00 |  |  |  |  |  |
Underwriting discounts and commissions | $ 3,139 |  |  |  |  |  |  |
Offering expenses paid | $ 4,861 |  |  |  |  |  |  |
Deferred offering costs |  |  |  |  | $ 4,861 | $ 4,861 |  | $ 63
Common Stock | Over-Allotment |  |  |  |  |  |  |  |
Company And Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Shares issued and sold | shares | 30,000 |  |  |  |  |  |  |
Shares issued and sold, price per share | $ / shares | $ 11.00 |  |  |  |  |  |  |

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