XML 43 R28.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Stockholders' Equity (Deficit) (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2021
Equity [Abstract] |
Summary of Stock Option Activity | Stock option activity for employee and nonemployee awards and related information is as follows (in thousands, except per share and contractual term data):
|  | Number of Options |  |  | Weighted- Average Exercise Price Per Share |  |  | Weighted- Average Remaining Contractual Term (in years) |  |  | Aggregate Intrinsic Value |
Outstanding at December 31, 2020 |  |  | 3,788 |  |  | $ | 9.06 |  |  |  |  |  |  |  |  |
Granted |  |  | 2,671 |  |  |  | 23.23 |  |  |  |  |  |  |  |  |
Exercised |  |  | (172 | ) |  |  | 5.42 |  |  |  |  |  |  |  |  |
Forfeited/expired |  |  | (509 | ) |  |  | 22.99 |  |  |  |  |  |  |  |  |
Outstanding at December 31, 2021 |  |  | 5,778 |  |  | $ | 14.49 |  |  |  | 8.5 |  |  | $ | 58,950 |
Vested and expected to vest at December 31, 2021 |  |  | 5,778 |  |  | $ | 14.49 |  |  |  | 8.5 |  |  | $ | 58,950 |
Exercisable at December 31, 2021 |  |  | 1,885 |  |  | $ | 8.91 |  |  |  | 7.8 |  |  | $ | 29,226 |
Schedule of Assumptions used in Black-Scholes Model to Determine Fair Value of Stock/Unit Option Grants and Shares Purchasable under ESPP | The assumptions used in the Black-Scholes model to determine the fair value of stock/unit option grants and shares purchasable under the ESPP were as follows:
|  | Year Ended December 31,
Stock/Unit Option Grants |  | 2021 |  | 2020 |  | 2019
Risk-free interest rate |  | 0.5% - 1.3% |  | 0.3% - 1.5% |  | 1.4% - 2.7%
Expected volatility |  | 86% - 88% |  | 88% - 92% |  | 84% - 88%
Expected term (in years) |  | 5.5 - 6.1 |  | 5.4 - 6.1 |  | 2.0 - 6.1
Expected dividend yield |  | —% |  | —% |  | —%
|  | Year Ended December 31,
ESPP |  | 2021 |  |  | 2020 |  | 2019
Risk-free interest rate |  | 0.1% |  |  | 0.1% - 0.2% |  | N/A
Expected volatility |  | 69% - 75% |  |  | 75% - 96% |  | N/A
Expected term (in years) |  | 0.5 |  |  | 0.5 |  | N/A
Expected dividend yield |  | —% |  |  | —% |  | N/A
Schedule of Allocated Stock-based Compensation Expense | The allocation of stock-based compensation expense was as follows (in thousands):
|  | Year Ended December 31, |
|  | 2021 |  |  | 2020 |  |  | 2019 |
Research and development expense |  | $ | 9,228 |  |  | $ | 1,895 |  |  | $ | 84 |
General and administrative expense |  |  | 7,828 |  |  |  | 2,415 |  |  |  | 322 |
Total stock-based compensation expense |  | $ | 17,056 |  |  | $ | 4,310 |  |  | $ | 406 |
Schedule of Common Stock Reserved for Future Issuance | Common stock reserved for future issuance consisted of the following (in thousands):
|  | December 31, |
|  | 2021 |  |  | 2020 |
Common stock options issued and outstanding |  |  | 5,778 |  |  |  | 3,788 |
Equity awards available for future issuance under equity plans |  |  | 2,575 |  |  |  | 2,852 |
Common stock authorized under the ESPP |  |  | 639 |  |  |  | 296 |
Total |  |  | 8,992 |  |  |  | 6,936 |

X
- Definition Schedule of common stock reserved for future issuance. + References No definition available. + Details
Name: | rna_ScheduleOfCommonStockReservedForFutureIssuanceTableTextBlock
Namespace Prefix: | rna_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Schedule of share based payment award stock options and employee stock purchase plan valuation assumptions. + References No definition available. + Details
Name: | rna_ScheduleOfShareBasedPaymentAwardStockOptionsAndEmployeeStockPurchasePlanValuationAssumptionsTableTextBlock
Namespace Prefix: | rna_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_EquityAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of allocation of amount expensed and capitalized for award under share-based payment arrangement to statement of income or comprehensive income and statement of financial position. Includes, but is not limited to, corresponding line item in financial statement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=122041274&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5047-113901 + Details
Name: | us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration