XML 30 R22.htm IDEA: XBRL DOCUMENT
v3.26.1

Marketable Securities and Fair Value Measurements (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2026
Available-for-Sale Marketable Securities and Fair Value Measurements [Abstract] |
Schedule of Fair Value Measurements on Cash Equivalents and Marketable Securities | The fair value measurements of the Company’s cash equivalents and marketable securities are identified at the following levels within the fair value hierarchy (in thousands):
| March 31, 2026 |
|  |  |  | Fair Value Measurement |
| Total |  |  | Level 1 |  |  | Level 2 |  |  | Level 3 |
Cash equivalents: |  |  |  |  |  |  |  |  |  |  |
Money market funds | $ | 48,411 |  |  | $ | 48,411 |  |  | $ | — |  |  | $ | — |
Commercial paper |  | 15,978 |  |  |  | — |  |  |  | 15,978 |  |  |  | — |
Corporate securities |  | 2,266 |  |  |  | — |  |  |  | 2,266 |  |  |  | — |
Marketable securities, current: |  |  |  |  |  |  |  |  |  |  |
U.S. treasury securities |  | 151,153 |  |  |  | — |  |  |  | 151,153 |  |  |  | — |
Corporate securities |  | 62,820 |  |  |  | — |  |  |  | 62,820 |  |  |  | — |
Commercial paper |  | 43,351 |  |  |  | — |  |  |  | 43,351 |  |  |  | — |
U.S. government agency securities |  | 18,472 |  |  |  | — |  |  |  | 18,472 |  |  |  | — |
Marketable securities, non-current: |  |  |  |  |  |  |  |  |  |  |
U.S. treasury securities |  | 126,328 |  |  |  | — |  |  |  | 126,328 |  |  |  | — |
Corporate securities |  | 32,682 |  |  |  | — |  |  |  | 32,682 |  |  |  | — |
U.S. government agency securities |  | 15,681 |  |  |  | — |  |  |  | 15,681 |  |  |  | — |
Total measured at fair value | $ | 517,142 |  |  | $ | 48,411 |  |  | $ | 468,731 |  |  | $ | — |
| As of December 31, 2025 |
|  |  |  | Fair Value Measurement |
| Total |  |  | Level 1 |  |  | Level 2 |  |  | Level 3 |
Cash equivalents: |  |  |  |  |  |  |  |  |  |  |
Money market funds | $ | 63,736 |  |  | $ | 63,736 |  |  | $ | — |  |  | $ | — |
Commercial paper |  | 50,163 |  |  |  | — |  |  |  | 50,163 |  |  |  | — |
Corporate securities |  | 2,190 |  |  |  | — |  |  |  | 2,190 |  |  |  | — |
Marketable securities, current: |  | — |  |  |  |  |  |  |  |  |  |
U.S. treasury securities |  | 141,984 |  |  |  | — |  |  |  | 141,984 |  |  |  | — |
Commercial paper |  | 67,784 |  |  |  | — |  |  |  | 67,784 |  |  |  | — |
Corporate securities |  | 32,573 |  |  |  | — |  |  |  | 32,573 |  |  |  | — |
U.S. government agency securities |  | 28,026 |  |  |  | — |  |  |  | 28,026 |  |  |  | — |
Marketable securities, non-current: |  | — |  |  |  |  |  |  |  |  |  |
U.S. treasury securities |  | 117,632 |  |  |  | — |  |  |  | 117,632 |  |  |  | — |
Corporate securities |  | 35,713 |  |  |  | — |  |  |  | 35,713 |  |  |  | — |
U.S. government agency securities |  | 4,224 |  |  |  | — |  |  |  | 4,224 |  |  |  | — |
Total measured at fair value | $ | 544,025 |  |  | $ | 63,736 |  |  | $ | 480,289 |  |  | $ | — |
Summary of Marketable Securities by Major Type of Security | As of March 31, 2026, the following table summarizes the amortized cost and the unrealized gains (losses) of the marketable securities presented within marketable securities and cash equivalents (in thousands):
|  | Remaining |  |  |  |  |  |  |  |  |  |  | Aggregate |
|  | Contractual |  |  |  |  |  |  |  |  |  |  | Estimated Fair |
|  | Maturity (in years) |  | Amortized Cost |  |  | Unrealized Gains |  |  | Unrealized Losses |  |  | Value |
U.S. treasury securities |  | Less than 1 |  | $ | 151,062 |  |  | $ | 124 |  |  | $ | (33 | ) |  | $ | 151,153 |
Corporate securities |  | Less than 1 |  |  | 65,210 |  |  |  | — |  |  |  | (124 | ) |  |  | 65,086 |
Commercial paper |  | Less than 1 |  |  | 59,348 |  |  |  | — |  |  |  | (19 | ) |  |  | 59,329 |
U.S. government agency securities |  | Less than 1 |  |  | 18,465 |  |  |  | 8 |  |  |  | (1 | ) |  |  | 18,472 |
Total maturity less than 1 year |  |  |  |  | 294,085 |  |  |  | 132 |  |  |  | (177 | ) |  |  | 294,040 |
U.S. treasury securities |  | 1 to 2 |  |  | 126,680 |  |  |  | 17 |  |  |  | (369 | ) |  |  | 126,328 |
Corporate securities |  | 1 to 2 |  |  | 32,802 |  |  |  | 4 |  |  |  | (124 | ) |  |  | 32,682 |
U.S. government agency securities |  | 1 to 2 |  |  | 15,733 |  |  |  | — |  |  |  | (52 | ) |  |  | 15,681 |
Total |  |  |  | $ | 469,300 |  |  | $ | 153 |  |  | $ | (722 | ) |  | $ | 468,731 |
As of December 31, 2025, the following table summarizes the amortized cost and the unrealized gains (losses) of the marketable securities presented within marketable securities and cash equivalents (in thousands):
|  | Remaining Contractual Maturity (in years) |  | Amortized Cost |  |  | Unrealized Gains |  |  | Unrealized Losses |  |  | Aggregate Estimated Fair Value |
Commercial paper |  | Less than 1 |  | $ | 117,939 |  |  | $ | 17 |  |  | $ | (9 | ) |  | $ | 117,947 |
U.S. treasury securities |  | Less than 1 |  |  | 141,688 |  |  |  | 296 |  |  |  | — |  |  |  | 141,984 |
Corporate securities |  | Less than 1 |  |  | 34,755 |  |  |  | 14 |  |  |  | (6 | ) |  |  | 34,763 |
U.S. government agency securities |  | Less than 1 |  |  | 27,992 |  |  |  | 34 |  |  |  | — |  |  |  | 28,026 |
Total maturity less than 1 year |  |  |  |  | 322,374 |  |  |  | 361 |  |  |  | (15 | ) |  |  | 322,720 |
U.S. treasury securities |  | 1 to 2 |  |  | 117,376 |  |  |  | 257 |  |  |  | (1 | ) |  |  | 117,632 |
Corporate securities |  | 1 to 2 |  |  | 35,699 |  |  |  | 24 |  |  |  | (10 | ) |  |  | 35,713 |
U.S. government agency securities |  | 1 to 2 |  |  | 4,223 |  |  |  | 2 |  |  |  | (1 | ) |  |  | 4,224 |
Total |  |  |  | $ | 479,672 |  |  | $ | 644 |  |  | $ | (27 | ) |  | $ | 480,289 |
Schedule of Unrealized Loss Positions of Marketable Securities | As of March 31, 2026, the following table summarizes marketable securities in an unrealized loss position (in thousands):
| Remaining Contractual Maturity (in years) |  | Fair Value |  |  | Gross Unrealized Loss |
Corporate securities | Less than 1 |  | $ | 64,093 |  |  | $ | (124 | )
Commercial paper | Less than 1 |  |  | 57,636 |  |  |  | (19 | )
U.S. treasury securities | Less than 1 |  |  | 49,876 |  |  |  | (33 | )
U.S. government agency securities | Less than 1 |  |  | 6,060 |  |  |  | (1 | )
Total maturity less than 1 year |  |  |  | 177,665 |  |  |  | (177 | )
U.S. treasury securities | 1 to 2 |  |  | 115,720 |  |  |  | (369 | )
Corporate securities | 1 to 2 |  |  | 29,168 |  |  |  | (124 | )
U.S. government agency securities | 1 to 2 |  |  | 15,681 |  |  |  | (52 | )
Total |  |  | $ | 338,234 |  |  | $ | (722 | )

X
- Definition Available-for-sale marketable securities and fair value measurements. + References No definition available. + Details
Name: | sepn_AvailableForSaleMarketableSecuritiesAndFairValueMeasurementsAbstract
Namespace Prefix: | sepn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 55 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479081/326-30-55-8 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-6 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479106/326-30-50-4 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of financial instrument measured at fair value on recurring or nonrecurring basis. Includes, but is not limited to, instrument classified in shareholders' equity. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration