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Common Stock and Warrants - Additional Information (Details) - USD ($) |  |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 9 Months Ended |
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Sep. 30, 2021 | Sep. 01, 2021 | Feb. 01, 2021 | Oct. 26, 2020 | Mar. 20, 2020 | Jan. 27, 2020 | Mar. 31, 2020 | Sep. 30, 2021 | Jun. 30, 2021 | Mar. 31, 2021 | Sep. 30, 2021 | Sep. 30, 2020 | Dec. 31, 2020
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock, shares authorized | 150,000,000 |  |  |  |  |  |  | 150,000,000 |  |  | 150,000,000 |  | 150,000,000
Common stock, par value | $ 0.001 |  |  |  |  |  |  | $ 0.001 |  |  | $ 0.001 |  | $ 0.001
Preferred stock, shares authorized | 10,000,000 |  |  |  |  |  |  | 10,000,000 |  |  | 10,000,000 |  | 10,000,000
Preferred stock, par value | $ 0.001 |  |  |  |  |  |  | $ 0.001 |  |  | $ 0.001 |  | $ 0.001
Common share, voting rights |  |  |  |  |  |  |  |  |  |  | one vote per share |  |
Common share, dividends declared |  |  |  |  |  |  |  |  |  |  | $ 0 |  |
Gross proceeds from issuance of common stock |  |  |  |  |  |  |  |  |  |  | $ 11,614,000 | $ 7,233,000 |
Minimum | LPC Purchase Agreement | Lincoln Park |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Average price of sale of common stock |  | $ 15.1661 |  |  |  |  |  |  |  |  |  |  |
Maximum | LPC Purchase Agreement | Lincoln Park |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Issuance of common stock outstanding percentage |  | 19.99% |  |  |  |  |  |  |  |  |  |  |
Common Stock | LPC Purchase Agreement | Lincoln Park |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Shares issued |  |  |  |  |  |  |  | 40,000 |  |  |  |  |
Net proceeds from issuance of common stock |  |  |  |  |  |  |  | $ 600,000 |  |  |  |  |
Agreement term |  | 36 months |  |  |  |  |  |  |  |  |  |  |
Number of shares issued for commitment fee |  |  |  |  |  |  |  | 31,958 |  |  |  |  |
Fair value of commitment fee |  |  |  |  |  |  |  | $ 500,000 |  |  |  |  |
Number of shares issuable in transaction |  | 20,000 |  |  |  |  |  |  |  |  |  |  |
Common Stock | Minimum | LPC Purchase Agreement | Lincoln Park |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Beneficially owned percentage |  | 9.99% |  |  |  |  |  |  |  |  |  |  |
Common Stock | Maximum | LPC Purchase Agreement | Lincoln Park |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term purchase commitment amount |  | $ 15,000,000.0 |  |  |  |  |  |  |  |  |  |  |
Consideration receivable per transaction |  | $ 2,000,000.0 |  |  |  |  |  |  |  |  |  |  |
2020 ATM |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Gross proceeds from issuance of common stock |  |  |  |  |  |  |  |  |  |  |  | $ 5,000,000.0 |
Price per share |  |  |  |  |  |  |  |  |  |  |  | $ 21.68 |
Offering expenses incurred |  |  |  |  |  |  |  |  |  |  |  | $ 181,000 |
2020 ATM | Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Shares issued |  |  |  |  |  |  |  |  |  |  |  | 2 |
2020 ATM | Form S3 Shelf Registration |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate offering amount |  |  |  |  |  | $ 11,340,000 | $ 9,150,000 |  |  |  |  |  |
March 2020 Offering |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Gross proceeds from issuance of common stock |  |  |  |  | $ 2,200,000 |  |  |  |  |  |  |  |
Price per share |  |  |  |  | $ 12.25 |  |  |  |  |  |  |  |
Warrants to purchase number of common stock, shares |  |  |  |  | 178,776 |  |  |  |  |  |  |  |
Warrant exercisable price per share |  |  |  |  | $ 16.10 |  |  |  |  |  |  |  |
Underwriting discounts and commissions paid |  |  |  |  | $ 300,000 |  |  |  |  |  |  |  |
Number of common stock converted by each warrant |  |  |  |  | 1 |  |  |  |  |  |  |  |
Warrants expiration date |  |  |  |  | Mar. 20, 2025 |  |  |  |  |  |  |  |
Fair value of warrants at issuance |  |  |  |  | $ 800,000 |  |  |  |  |  |  |  |
Class of warrants exercised | 81,633 |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from the exercise of warrants |  |  |  |  |  |  |  |  |  | $ 1,300,000 |  |  |
March 2020 Offering | Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Shares issued |  |  |  |  | 178,776 |  |  |  |  |  |  |  |
October 2020 Offering |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Shares issued |  |  |  | 187,646 |  |  |  |  |  |  |  |  |
Gross proceeds from issuance of common stock |  |  |  | $ 3,400,000 |  |  |  |  |  |  |  |  |
Price per share |  |  |  | $ 18.20 |  |  |  |  |  |  |  |  |
Warrants to purchase number of common stock, shares |  |  |  | 93,817 |  |  |  |  |  |  |  |  |
Warrant exercisable price per share |  |  |  | $ 15.82 |  |  |  |  |  |  |  |  |
Fair value of warrants at issuance |  |  |  | $ 600,000 |  |  |  |  |  |  |  |  |
Share issuance cost including placement agent fees |  |  |  | $ 300,000 |  |  |  |  |  |  |  |  |
Warrants expiration period |  |  |  | 3 years |  |  |  |  |  |  |  |  |
Percentage of right to participate subsequent financing |  |  |  | 30.00% |  |  |  |  |  |  |  |  |
October 2020 Offering | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Subscription to participate subsequent financing |  |  |  | $ 250,000 |  |  |  |  |  |  |  |  |
October 2020 Offering | Officer, Affiliates of an Officer and Director |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Price per share |  |  |  | $ 18.354 |  |  |  |  |  |  |  |  |
Warrant exercisable price per share |  |  |  | $ 16.1665 |  |  |  |  |  |  |  |  |
October 2020 Offering | Placement Agent |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Shares issued |  |  |  | 961 |  |  |  |  |  |  |  |  |
Price per share |  |  |  | $ 19.775 |  |  |  |  |  |  |  |  |
October 2020 Offering | Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Number of common stock converted by each warrant |  |  |  | 0.50 |  |  |  |  |  |  |  |  |
Common unit issued |  |  |  | 1 |  |  |  |  |  |  |  |  |
February 2021 Offering |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Price per share |  |  | $ 14.82 |  |  |  |  |  |  |  |  |  |
Warrants to purchase number of common stock, shares |  |  | 372,468 |  |  |  |  |  |  |  |  |  |
Warrant exercisable price per share |  |  | $ 16.302 |  |  |  |  |  |  |  |  |  |
Number of common stock converted by each warrant |  |  | 0.50 |  |  |  |  |  |  |  |  |  |
Fair value of warrants at issuance |  |  | $ 2,600,000 |  |  |  |  |  |  |  |  |  |
Class of warrants exercised | 262 |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from the exercise of warrants |  |  |  |  |  |  |  |  | $ 4,000 |  |  |  |
Warrants expiration period |  |  | 5 years |  |  |  |  |  |  |  |  |  |
Net proceeds from issuance of common stock |  |  | $ 9,600,000 |  |  |  |  |  |  |  |  |  |
February 2021 Offering | Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Shares issued |  |  | 744,936 |  |  |  |  |  |  |  |  |  |
Over-Allotment Option |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Price per share |  |  | $ 18.525 |  |  |  |  |  |  |  |  |  |
Over-Allotment Option | Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Shares issued |  |  | 29,797 |  |  |  |  |  |  |  |  |  |
Closing Sale Price 1 | Common Stock | LPC Purchase Agreement | Lincoln Park |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Price per share |  | $ 20.00 |  |  |  |  |  |  |  |  |  |  |
Closing Sale Price 1 | Common Stock | Maximum | LPC Purchase Agreement | Lincoln Park |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares issuable in transaction |  | 25,000 |  |  |  |  |  |  |  |  |  |  |
Closing Sale Price 2 | Common Stock | LPC Purchase Agreement | Lincoln Park |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Price per share |  | $ 25.00 |  |  |  |  |  |  |  |  |  |  |
Closing Sale Price 2 | Common Stock | Maximum | LPC Purchase Agreement | Lincoln Park |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares issuable in transaction |  | 30,000 |  |  |  |  |  |  |  |  |  |  |
Class A Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule Of Stockholders Equity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock, shares authorized | 150,000,000 |  |  |  |  |  |  | 150,000,000 |  |  | 150,000,000 |  |
Common stock, par value | $ 0.001 |  |  |  |  |  |  | $ 0.001 |  |  | $ 0.001 |  |

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