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

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The increase or decrease in number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding, including vested options.

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Number of shares issued under share-based payment arrangement.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Stock-Based Compensation - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 22, 2023	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2016	Jan. 01, 2024	Jan. 01, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation		$ 8,700	$ 1,900	$ 22,517	$ 3,620
Two Thousand And Fifteen And Two Thousand And Sixteen Equity Incentive Plan And Two Thousand And Eighteen Equity Inducement Plan \| Service Based Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vest period grant date				4 years
Share-based payment award, term				10 years
Two Thousand And Fifteen Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares subject to options outstanding (in shares)				3,029
2016 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Annual percentage of additional shares						5.00%
Additional number of shares available for issuance (in shares)							3,023,650	104,561
Common stock available for future issuance (in shares)		7,336,181		7,336,181
Outstanding option awards (in shares)		3,024,766		3,024,766
2018 Equity Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock available for future issuance (in shares)		6,028,000		6,028,000
Outstanding option awards (in shares)		5,682,341		5,682,341
Spyre 2023 Equity Incentive Plan \| Asset Acquisition
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of outstanding and unexercised stock options to purchase (in shares)	2,734
Parapyre Option Obligation
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Pro-rated estimated fair value of options				$ 6,900
Stock-based compensation		$ 1,500	$ 200	6,900	$ 200
Unamortized expense		$ 7,000		$ 7,000
2016 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued (in shares)				2,330	1,793