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Stockholders' Equity - Narrative (Details) |  |  | 1 Months Ended | 12 Months Ended | 20 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | ---
Mar. 02, 2020 shares | Nov. 26, 2019 $ / shares shares | Jun. 30, 2020 USD ($) $ / shares shares | Dec. 31, 2021 USD ($) vote shares | Dec. 31, 2020 USD ($) shares | Dec. 31, 2019 USD ($) shares | Dec. 31, 2013 $ / shares shares | Dec. 31, 2021 USD ($) shares | May 31, 2020 USD ($) | Jul. 31, 2018 USD ($)
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Preferred stock, shares authorized (in shares) |  |  |  | 25,000,000 | 25,000,000 |  |  | 25,000,000 |  |
Preferred stock, shares issued (in shares) |  |  |  | 0 | 0 |  |  | 0 |  |
Number of shares into which warrant issued during period may be converted |  |  |  |  |  |  | 129,491 |  |  |
Warrant exercise price per share (in dollars per share) | $ / shares |  |  |  |  |  |  | $ 0.05 |  |  |
Contractual life of warrants |  |  |  |  |  |  | 10 years |  |  |
Warrants outstanding (in shares) |  |  |  | 39,474 | 39,474 |  |  | 39,474 |  |
Common stock issued upon exercise of warrant (in shares) |  |  |  | 0 |  |  |  |  |  |
Number of shares reserved for future issuance (in shares) |  |  |  | 9,199,512 | 6,869,189 |  |  | 9,199,512 |  |
Common Stock |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Issuance of common upon exercise of warrant (in shares) | 2,574,971 |  |  |  |  |  |  |  |  |
Number of votes per common share | vote |  |  |  | 1 |  |  |  |  |  |
Exchange Warrants |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Warrant exercise price per share (in dollars per share) | $ / shares |  | $ 0.0001 |  |  |  |  |  |  |  |
Warrants outstanding (in shares) |  |  |  | 2,575,000 |  |  |  | 2,575,000 |  |
Number of common shares exchanged for warrants (in shares) |  | 2,575,000 |  |  |  |  |  |  |  |
Number of shares of common stock into which warrants may be converted (in shares) |  | 2,575,000 |  |  |  |  |  |  |  |
Warrants and share-based payment awards |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Number of shares reserved for future issuance (in shares) |  |  |  | 9,199,512 | 6,869,189 |  |  | 9,199,512 |  |
At market equity offering program (2018 ATM) |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Amount of shares authorized to be offered and sold | $ |  |  |  |  |  |  |  |  |  | $ 75,000,000
Proceeds from issuance of common stock | $ |  |  |  |  | $ 62,976,000 |  |  |  |  |
At market equity offering program (2018 ATM) | Common Stock |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Number of shares sold (in shares) |  |  |  |  | 10,900,599 |  |  |  |  |
At market equity offering program (2018 ATM) | Additional Paid-in Capital |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Proceeds from issuance of common stock | $ |  |  |  |  | $ 62,976,000 |  |  |  |  |
At Market Equity Offering Program (2020 ATM) |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Amount of shares authorized to be offered and sold | $ |  |  |  |  |  |  |  |  | $ 100,000,000 |
Proceeds from issuance of common stock | $ |  |  |  |  |  |  |  | $ 43,087,000 |  |
At Market Equity Offering Program (2020 ATM) | Common Stock |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Number of shares sold (in shares) |  |  |  |  |  |  |  | 3,961,074 |  |
Public Stock Offering |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Number of shares sold (in shares) |  |  | 9,200,000 |  |  |  |  |  |  |
Proceeds from issuance of common stock | $ |  |  |  | $ 0 | $ 163,990,000 | $ 92,162,000 |  |  |  |
Shares sold, price per share (in dollars per share) | $ / shares |  |  | $ 19.00 |  |  |  |  |  |  |
Proceeds from stock issuance, net of issuance costs | $ |  |  | $ 163,990,000 |  |  |  |  |  |  |
Public Stock Offering | Common Stock |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Number of shares sold (in shares) |  |  |  |  | 9,200,000 | 24,437,500 |  |  |  |

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