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Subsequent Events - Additional Information (Detail) $ / shares in Units, $ in Millions | Aug. 03, 2020 USD ($) $ / shares shares | Jul. 31, 2020 shares | Jul. 01, 2020 USD ($) $ / shares shares | Jun. 30, 2020 shares | Dec. 31, 2019 shares
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Subsequent Event [Line Items] |  |  |  |  |
Common stock, shares authorized | shares |  |  |  | 150,000,000 | 150,000,000
Subsequent Event [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Reverse stock split ratio |  | 0.05 |  |  |
Reverse stock split, description |  | On July 29, 2020, we filed a certificate of amendment to our Second Amended and Restated Certificate of Incorporation, as amended, and effected as of July 31, 2020 a 1-for-20 reverse stock split of our issued and outstanding shares of common stock. As a result of the reverse stock split, each 20 shares of the outstanding common stock were combined into one share of common stock without any change to the par value per share |  |  |
Common stock, shares authorized | shares |  | 150,000,000 |  |  |
Subsequent Event [Member] | Direct Offering [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Aggregate percentage of gross proceeds paid as cash fee for placement agent and advisor |  |  | 8.00% |  |
Gross proceeds from issuance of common stock | $ |  |  | $ 6.0 |  |
Placement agent fees and offering expenses | $ |  |  | 0.5 |  |
Proceeds from issuance of common stock | $ |  |  | $ 5.5 |  |
Subsequent Event [Member] | August 2020 Public Offering [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Gross proceeds from issuance of common stock | $ | $ 7.5 |  |  |  |
Proceeds from issuance of common stock | $ | 6.8 |  |  |  |
Underwriting discounts and commissions and offering expenses | $ | $ 0.7 |  |  |  |
Subsequent Event [Member] | August 2020 Public Offering [Member] | Pre-Funded Warrant [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Warrants to purchase common stock | shares | 142,857 |  |  |  |
Pre-funded warrant, offering price per share | $ / shares | $ 10.499 |  |  |  |
Subsequent Event [Member] | Common Stock [Member] | Direct Offering [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Shares issued, Shares | shares |  |  | 731,707 |  |
Common stock, price per share | $ / shares |  |  | $ 8.20 |  |
Subsequent Event [Member] | Common Stock [Member] | August 2020 Public Offering [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Shares issued, Shares | shares | 569,043 |  |  |  |
Common stock, price per share | $ / shares | $ 10.50 |  |  |  |
Subsequent Event [Member] | Common Stock [Member] | August 2020 Public Offering [Member] | Pre-Funded Warrant [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Pre-funded warrant, exercise price per share | $ / shares | $ 0.001 |  |  |  |
Number of days of prior notice to achieve not in excess percentage of common stock shares owned by warrant holder | 61 days |  |  |  |
Subsequent Event [Member] | Common Stock [Member] | August 2020 Public Offering [Member] | Pre-Funded Warrant [Member] | Minimum [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Percentage of shares of common stock owned by warrant holder | 9.99% |  |  |  |
Subsequent Event [Member] | Common Stock [Member] | August 2020 Public Offering [Member] | Pre-Funded Warrant [Member] | Maximum [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Percentage of shares of common stock owned by warrant holder | 19.99% |  |  |  |
Subsequent Event [Member] | Common Stock [Member] | Underwriters Over-Allotment Option Exercise [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Shares issued, Shares | shares | 92,856 |  |  |  |

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