Stock-Based Compensation - Summary of Stock Options Activity under Plans (Details) $ / shares in Units, $ in Thousands	6 Months Ended
Jun. 30, 2022 USD ($) $ / shares shares
Share-based Payment Arrangement [Abstract]
Stock Options Outstanding Balance at December 31, 2021 \| shares	8,640,951
Stock Options Outstanding Options granted \| shares	8,828,368
Stock Options Outstanding Options exercised \| shares	0
Stock Options Outstanding Options forfeited/cancelled \| shares	(1,678,488)
Stock Options Outstanding Options expired \| shares	(692,913)
Stock Options Outstanding Balance at June 30, 2022 \| shares	15,097,918
Stock Options Outstanding Vested and expected to vest at June 30, 2022 \| shares	15,097,918
Stock Options Outstanding Vested and exercisable at June 30, 2022 \| shares	3,113,396
Weighted-Average Exercise Price Balance at December 31, 2021 \| $ / shares	$ 4.74
Weighted-Average Exercise Price Options granted \| $ / shares	0.84
Weighted-Average Exercise Price Options exercised \| $ / shares	0
Weighted-Average Exercise Price Options forfeited/cancelled \| $ / shares	3.48
Weighted-Average Exercise Price Options expired \| $ / shares	6.23
Weighted-Average Exercise Price Balance at June 30, 2022 \| $ / shares	2.53
Weighted-Average Exercise Price Vested and expected to vest at June 30, 2022 \| $ / shares	2.53
Weighted-Average Exercise Price Vested and exercisable at June 30, 2022 \| $ / shares	$ 5.72
Weighted-Average Remaining Contractual Term (in years) Balance at June 30, 2022	8 years 7 months 20 days
Weighted-Average Remaining Contractual Term (in years) Vested and expected to vest at June 30, 2022	8 years 7 months 6 days
Weighted-Average Remaining Contractual Term (in years) Vested and exercisable at June 30, 2022	4 years 8 months 26 days
Aggregate Intrinsic Value Balance at June 30, 2022 \| $	$ 48
Aggregate Intrinsic Value Vested and expected to vest at June 30, 2022 \| $	48
Aggregate Intrinsic Value Vested and exercisable at June 30, 2022 \| $	$ 0

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of fully vested and expected to vest exercisable options that may be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for fully vested and expected to vest exercisable or convertible options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of share options (or share units) exercised during the current period.

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