| Document and Entity Information | 12 Months Ended |
| Dec. 31, 2022 | |
| Cover [Abstract] | |
| Document Type | DEF 14A |
| Amendment Flag | false |
| Entity Registrant Name | Karyopharm Therapeutics Inc. |
| Entity Central Index Key | 0001503802 |
| Pay vs Performance Disclosure - USD ($) | 4 Months Ended | 12 Months Ended | 20 Months Ended | ||
| May 03, 2021 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2022 | |
| Pay vs Performance Disclosure [Table] | |||||
| Pay vs Performance [Table Text Block] | Pay Versus Performance Value of Initial Fixed $100 Investment Based On: Year Summary Summary Compensation Compensation Average Average Total Peer Group Net Company Net Product 2022 N/A 6,910,015 N/A 1,559,966 2,891,674 1,670,016 17.74 113.65 ( 165,291,065 ) 120,444,930 2021 3,069,589 8,355,172 ( 1,074,531 ) 5,402,741 2,004,146 ( 305,039 ) 33.54 126.45 ( 124,087,976 ) 98,435,969 2020 3,937,039 N/A 1,793,017 N/A 2,968,850 1,460,323 80.75 126.42 ( 196,273,469 ) 76,209,631 (1) For 2022, our PEO was Mr. Paulson who was appointed as our President and Chief Executive Officer effective May 2, 2021 (“Second PEO”), and our Other NEOs were Mr. Mason, Ms. Cheng, Mr. Mano, Mr. Poulton, Mr. Frenkel, our former Chief Development Officer, and Dr. Shacham, our former President and Chief Scientific Officer. For 2021, our PEOs were Dr. Kauffman , who served as our Chief Executive Officer until May 3, 2021 (“First PEO”), and Mr. Paulson, and our Other NEOs were Mr. Mason, Mr. Frenkel, Dr. Shacham, and Dr. Shah, our former Chief Medical Officer. For 2020, our PEO was Dr. Kauffman and our Other NEOs were Mr. Mason and Dr. Shacham. (2) The following table describes the adjustments, each of which is prescribed by SEC rules, to calculate the CAP Amounts from the SCT Amoun ts. The SCT Amounts and the CAP Amounts do not reflect the actual amount of compensation earned by or paid to our executives during the applicable years, but rather are amounts determined in accordance with Item 402 of Regulation S-K under the Exchange Act. No awards vested in the year they were granted. 2022 ($) 2021 ($) 2020 ($) Adjustments First Second PEO Other NEOs* First Second PEO Other First Second PEO Other NEOs* Total Compensation from SCT(1) — 6,910,015 2,891,674 3,069,589 8,355,172 2,004,146 3,937,039 — 2,968,850 Adjustments for defined benefit and actuarial pension plans: Not applicable Adjustments for stock and option awards (Subtract): Aggregate value for stock awards and option awards included in SCT for the covered fiscal year — ( 5,545,772 ) ( 2,095,082 ) ( 2,340,049 ) ( 7,086,583 ) ( 1,302,726 ) ( 2,950,785 ) — ( 2,316,987 ) Add: Fair value at year end of awards granted during the covered fiscal year that were outstanding and unvested at the covered fiscal year end — 1,611,947 511,965 847,392 4,468,563 481,405 2,377,252 — 1,866,622 Add (Subtract): Change as of the end of the covered fiscal year (from the end of the prior fiscal year) in fair value of awards granted in any prior fiscal year that were outstanding and unvested at the covered fiscal year end — ( 1,339,720 ) ( 111,302 ) ( 1,919,745 ) ( 136,675 ) ( 1,093,312 ) ( 982,194 ) — ( 653,536 ) Add (Subtract): Change as of the vesting date (from the end of the prior fiscal year) in fair value of awards granted in any prior fiscal year for which vesting conditions were satisfied during the covered fiscal year — ( 76,504 ) 472,761 ( 731,718 ) ( 197,736 ) ( 394,552 ) ( 588,295 ) — ( 404,627 ) CAP Amounts (as calculated) — 1,559,966 1,670,016 ( 1,074,531 ) 5,402,741 ( 305,039 ) 1,793,017 — 1,460,323 | ||||
| Company Selected Measure Name | Net ProductRevenue | ||||
| Named Executive Officers, Footnote [Text Block] | (1) For 2022, our PEO was Mr. Paulson who was appointed as our President and Chief Executive Officer effective May 2, 2021 (“Second PEO”), and our Other NEOs were Mr. Mason, Ms. Cheng, Mr. Mano, Mr. Poulton, Mr. Frenkel, our former Chief Development Officer, and Dr. Shacham, our former President and Chief Scientific Officer. For 2021, our PEOs were Dr. Kauffman , who served as our Chief Executive Officer until May 3, 2021 (“First PEO”), and Mr. Paulson, and our Other NEOs were Mr. Mason, Mr. Frenkel, Dr. Shacham, and Dr. Shah, our former Chief Medical Officer. For 2020, our PEO was Dr. Kauffman and our Other NEOs were Mr. Mason and Dr. Shacham. | ||||
| Adjustment To PEO Compensation, Footnote [Text Block] | (2) The following table describes the adjustments, each of which is prescribed by SEC rules, to calculate the CAP Amounts from the SCT Amoun ts. The SCT Amounts and the CAP Amounts do not reflect the actual amount of compensation earned by or paid to our executives during the applicable years, but rather are amounts determined in accordance with Item 402 of Regulation S-K under the Exchange Act. No awards vested in the year they were granted. 2022 ($) 2021 ($) 2020 ($) Adjustments First Second PEO Other NEOs* First Second PEO Other First Second PEO Other NEOs* Total Compensation from SCT(1) — 6,910,015 2,891,674 3,069,589 8,355,172 2,004,146 3,937,039 — 2,968,850 Adjustments for defined benefit and actuarial pension plans: Not applicable Adjustments for stock and option awards (Subtract): Aggregate value for stock awards and option awards included in SCT for the covered fiscal year — ( 5,545,772 ) ( 2,095,082 ) ( 2,340,049 ) ( 7,086,583 ) ( 1,302,726 ) ( 2,950,785 ) — ( 2,316,987 ) Add: Fair value at year end of awards granted during the covered fiscal year that were outstanding and unvested at the covered fiscal year end — 1,611,947 511,965 847,392 4,468,563 481,405 2,377,252 — 1,866,622 Add (Subtract): Change as of the end of the covered fiscal year (from the end of the prior fiscal year) in fair value of awards granted in any prior fiscal year that were outstanding and unvested at the covered fiscal year end — ( 1,339,720 ) ( 111,302 ) ( 1,919,745 ) ( 136,675 ) ( 1,093,312 ) ( 982,194 ) — ( 653,536 ) Add (Subtract): Change as of the vesting date (from the end of the prior fiscal year) in fair value of awards granted in any prior fiscal year for which vesting conditions were satisfied during the covered fiscal year — ( 76,504 ) 472,761 ( 731,718 ) ( 197,736 ) ( 394,552 ) ( 588,295 ) — ( 404,627 ) CAP Amounts (as calculated) — 1,559,966 1,670,016 ( 1,074,531 ) 5,402,741 ( 305,039 ) 1,793,017 — 1,460,323 | ||||
| Non-PEO NEO Average Total Compensation Amount | $ 2,891,674 | $ 2,004,146 | $ 2,968,850 | ||
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 1,670,016 | (305,039) | 1,460,323 | ||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | Compensation Actually Paid vs. TSR | ||||
| Compensation Actually Paid vs. Net Income [Text Block] | Compensation Actually Paid vs. Net Income | ||||
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | Compensation Actually Paid vs. Net Product Revenue | ||||
| Tabular List [Table Text Block] | The following table identifies five financial and non-financial performance measures that, in our assessment, represent the most important performance measures we used to link the CAP Amounts for our NEOs for 2022 (our most recently completed fiscal year), to company performance. Of these measures, we have identified Net Product Revenue as the most important of our financial performance measures used to link CAP Amounts for our executives for 2022 to Company performance. 2022 Performance Measures Net Product Revenue License and Other Revenue Year-end Cash Adherence to Budget Clinical Trial Execution | ||||
| Total Shareholder Return Amount | $ 17.74 | 33.54 | 80.75 | ||
| Peer Group Total Shareholder Return Amount | 113.65 | 126.45 | 126.42 | ||
| Net Income (Loss) | $ (165,291,065) | $ (124,087,976) | $ (196,273,469) | ||
| Company Selected Measure Amount | 120,444,930 | 98,435,969 | 76,209,631 | ||
| PEO Name | Dr. Kauffman | Dr. Kauffman | Mr. Paulson | ||
| Measure [Axis]: 1 | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Measure Name | Net Product Revenue | ||||
| Measure [Axis]: 2 | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Measure Name | License and Other Revenue | ||||
| Measure [Axis]: 3 | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Measure Name | Year-end Cash | ||||
| Measure [Axis]: 4 | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Measure Name | Adherence to Budget | ||||
| Measure [Axis]: 5 | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Measure Name | Clinical Trial Execution | ||||
| Dr. Kauffman [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| PEO Total Compensation Amount | $ 0 | $ 3,069,589 | $ 3,937,039 | ||
| PEO Actually Paid Compensation Amount | 0 | (1,074,531) | 1,793,017 | ||
| Mr. Paulson [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| PEO Total Compensation Amount | 6,910,015 | 8,355,172 | 0 | ||
| PEO Actually Paid Compensation Amount | 1,559,966 | 5,402,741 | 0 | ||
| PEO [Member] | Dr. Kauffman [Member] | Aggregate value for stock awards and option awards included in SCT for the covered fiscal year [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | 0 | (2,340,049) | (2,950,785) | ||
| PEO [Member] | Dr. Kauffman [Member] | Fair value at year end of awards granted during the covered fiscal year that were outstanding and unvested at the covered fiscal year end [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | 0 | 847,392 | 2,377,252 | ||
| PEO [Member] | Dr. Kauffman [Member] | Change as of the end of the covered fiscal year (from the end of the prior fiscal year) in fair value of awards granted in any prior fiscal year that were outstanding and unvested at the covered fiscal year end [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | 0 | (1,919,745) | (982,194) | ||
| PEO [Member] | Dr. Kauffman [Member] | Change as of the vesting date (from the end of the prior fiscal year) in fair value of awards granted in any prior fiscal year for which vesting conditions were satisfied during the covered fiscal year [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | 0 | (731,718) | (588,295) | ||
| PEO [Member] | Mr. Paulson [Member] | Aggregate value for stock awards and option awards included in SCT for the covered fiscal year [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | (5,545,772) | (7,086,583) | 0 | ||
| PEO [Member] | Mr. Paulson [Member] | Fair value at year end of awards granted during the covered fiscal year that were outstanding and unvested at the covered fiscal year end [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | 1,611,947 | 4,468,563 | 0 | ||
| PEO [Member] | Mr. Paulson [Member] | Change as of the end of the covered fiscal year (from the end of the prior fiscal year) in fair value of awards granted in any prior fiscal year that were outstanding and unvested at the covered fiscal year end [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | (1,339,720) | (136,675) | 0 | ||
| PEO [Member] | Mr. Paulson [Member] | Change as of the vesting date (from the end of the prior fiscal year) in fair value of awards granted in any prior fiscal year for which vesting conditions were satisfied during the covered fiscal year [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | (76,504) | (197,736) | 0 | ||
| Non-PEO NEO [Member] | Aggregate value for stock awards and option awards included in SCT for the covered fiscal year [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | (2,095,082) | (1,302,726) | (2,316,987) | ||
| Non-PEO NEO [Member] | Fair value at year end of awards granted during the covered fiscal year that were outstanding and unvested at the covered fiscal year end [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | 511,965 | 481,405 | 1,866,622 | ||
| Non-PEO NEO [Member] | Change as of the end of the covered fiscal year (from the end of the prior fiscal year) in fair value of awards granted in any prior fiscal year that were outstanding and unvested at the covered fiscal year end [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | (111,302) | (1,093,312) | (653,536) | ||
| Non-PEO NEO [Member] | Change as of the vesting date (from the end of the prior fiscal year) in fair value of awards granted in any prior fiscal year for which vesting conditions were satisfied during the covered fiscal year [Member] | |||||
| Pay vs Performance Disclosure [Table] | |||||
| Adjustment to Compensation Amount | $ 472,761 | $ (394,552) | $ (404,627) | ||
