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Pay vs Performance Disclosure - USD ($)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Pay vs Performance Disclosure          
Pay vs Performance Disclosure, Table
​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Year-end value
of $100 invested
on 12/31/2019 in:
​ ​ ​ ​ ​ ​ ​
Year
​ ​
Summary
Compensation
Table
Total for
the First
PEO (1)
$
​ ​
Summary
Compensation
Table
Total for
the Second
PEO(2)
$
​ ​
Compensation
Actually
Paid to
the First
PEO (3)(4)
$
​ ​
Compensation
Actually
Paid to
the Second
PEO (3)(4)
$
​ ​
Average
Summary
Compensation
Table
Total for
Non-PEO
NEOs (5)
$
​ ​
Average
Compensation
Actually
Paid to
Non-PEO
NEOs (3)(4)(5)
$
​ ​
MRSN
Total
Shareholder
Return
$
​ ​
Peer
Group
Total
Shareholder
Return (6)
$
​ ​
Net
Loss
(in
millions)
$
​
2024
​ ​ ​ ​ 1,613,754 ​ ​ ​ ​ ​ N/A ​ ​ ​ ​ ​ 29,170 ​ ​ ​ ​ ​ N/A ​ ​ ​ ​ ​ 1,451,735 ​ ​ ​ ​ ​ 920,602 ​ ​ ​ ​ ​ 24.96 ​ ​ ​ ​ ​ 118.20 ​ ​ ​ ​ ​ (69.2) ​ ​
2023
​ ​ ​ ​ 2,601,249 ​ ​ ​ ​ ​ 4,450,009 ​ ​ ​ ​ ​ 4,357,982 ​ ​ ​ ​ ​ (353,115) ​ ​ ​ ​ ​ 1,706,840 ​ ​ ​ ​ ​ 495,789 ​ ​ ​ ​ ​ 40.49 ​ ​ ​ ​ ​ 118.87 ​ ​ ​ ​ ​ (171.7) ​ ​
2022
​ ​ ​ ​ N/A ​ ​ ​ ​ ​ 2,846,107 ​ ​ ​ ​ ​ N/A ​ ​ ​ ​ ​ 2,407,467 ​ ​ ​ ​ ​ 1,223,572 ​ ​ ​ ​ ​ 1,079,403 ​ ​ ​ ​ ​ 102.27 ​ ​ ​ ​ ​ 113.65 ​ ​ ​ ​ ​ (204.2) ​ ​
2021
​ ​ ​ ​ N/A ​ ​ ​ ​ ​ 8,277,490 ​ ​ ​ ​ ​ N/A ​ ​ ​ ​ ​ (6,779,152) ​ ​ ​ ​ ​ 2,409,043 ​ ​ ​ ​ ​ (1,407,347) ​ ​ ​ ​ ​ 108.55 ​ ​ ​ ​ ​ 126.45 ​ ​ ​ ​ ​ (170.1) ​ ​
2020
​ ​ ​ ​ N/A ​ ​ ​ ​ ​ 2,537,911 ​ ​ ​ ​ ​ N/A ​ ​ ​ ​ ​ 16,408,361 ​ ​ ​ ​ ​ 2,005,448 ​ ​ ​ ​ ​ 6,137,850 ​ ​ ​ ​ ​ 464.40 ​ ​ ​ ​ ​ 126.42 ​ ​ ​ ​ ​ (88.0) ​ ​
​
(1)
Martin Huber, M.D., or the First PEO, was appointed our President and Chief Executive Officer on September 11, 2023 and was the PEO for 2024.
​
(2)
Anna Protopapas, or the Second PEO, served as our President and Chief Executive Officer until September 10, 2023 and was the PEO 2022, 2021 and 2020.
​
(3)
The following tables describe deductions from, and additions to, total compensation in the Summary Compensation Table by year to calculate CAP. The Summary Compensation Table Amounts and CAP 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. Certain amounts reflected for fiscal year 2023 have been revised in select instances in order to incorporate administrative updates.
​
​ ​ ​
2024
​ ​
2023
​ ​
2022
​ ​
2021
​ ​
2020
​
​ ​ ​
First
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
First
PEO
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​
Total Compensation from Summary Compensation Table
​ ​ ​ $ 1,613,754 ​ ​ ​ ​ $ 1,451,735 ​ ​ ​ ​ $ 2,601,249 ​ ​ ​ ​ $ 4,450,009 ​ ​ ​ ​ $ 1,706,840 ​ ​ ​ ​ $ 2,846,107 ​ ​ ​ ​ $ 1,223,572 ​ ​ ​ ​ $ 8,277,490 ​ ​ ​ ​ $ 2,409,043 ​ ​ ​ ​ $ 2,537,911 ​ ​ ​ ​ $ 2,005,448 ​ ​
Adjustments for Pension ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Adjustment Summary Compensation Table Pension
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Amount added for current year service cost
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Amount added for prior service cost impacting current year
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Total Adjustments for Pension
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Adjustments for Equity Awards ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Adjustment for grant date values
in the Summary Compensation
Table
​ ​ ​ $ (651,679) ​ ​ ​ ​ $ (797,723) ​ ​ ​ ​ $ (2,013,740) ​ ​ ​ ​ $ (3,776,707) ​ ​ ​ ​ $ (1,141,206) ​ ​ ​ ​ $ (1,798,507) ​ ​ ​ ​ $ (553,715) ​ ​ ​ ​ $ (7,425,154) ​ ​ ​ ​ $ (1,981,419) ​ ​ ​ ​ $ (1,656,411) ​ ​ ​ ​ $ (1,550,241) ​ ​
Year-end fair value of unvested awards granted in the current year
​ ​ ​ $ 241,809 ​ ​ ​ ​ $ 296,000 ​ ​ ​ ​ $ 3,636,092 ​ ​ ​ ​ $ 510,197 ​ ​ ​ ​ $ 347,755 ​ ​ ​ ​ $ 1,441,729 ​ ​ ​ ​ $ 443,870 ​ ​ ​ ​ $ 1,538,348 ​ ​ ​ ​ $ 430,621 ​ ​ ​ ​ $ 7,965,820 ​ ​ ​ ​ $ 3,341,447 ​ ​
Year-over-year difference of
year-end fair values for unvested
awards granted in prior years
​ ​ ​ $ (1,041,598) ​ ​ ​ ​ $ (138,616) ​ ​ ​ ​ $ — ​ ​ ​ ​ $ (643,200) ​ ​ ​ ​ $ (220,779) ​ ​ ​ ​ $ (196,374) ​ ​ ​ ​ $ (58,449) ​ ​ ​ ​ $ (6,105,508) ​ ​ ​ ​ $ (1,108,788) ​ ​ ​ ​ $ 5,655,169 ​ ​ ​ ​ $ 1,717,834 ​ ​
Fair values at vest date for awards
granted and vested in current
year
​ ​ ​ $ 81,272 ​ ​ ​ ​ $ 99,487 ​ ​ ​ ​ $ 31,811 ​ ​ ​ ​ $ 229,104 ​ ​ ​ ​ $ 54,374 ​ ​ ​ ​ $ 226,105 ​ ​ ​ ​ $ 69,615 ​ ​ ​ ​ $ 567,422 ​ ​ ​ ​ $ 99,283 ​ ​ ​ ​ $ 822,260 ​ ​ ​ ​ $ 215,235 ​ ​
Difference in fair values between prior year-end fair values and vest date fair values for awards granted in prior years
​ ​ ​ $ (214,389) ​ ​ ​ ​ $ 9,719 ​ ​ ​ ​ $ 102,570 ​ ​ ​ ​ $ (281,491) ​ ​ ​ ​ $ (84,633) ​ ​ ​ ​ $ (111,593) ​ ​ ​ ​ $ (45,490) ​ ​ ​ ​ $ (3,631,751) ​ ​ ​ ​ $ (661,387) ​ ​ ​ ​ $ 1,083,613 ​ ​ ​ ​ $ 408,127 ​ ​
Forfeitures during current year equal to prior year-end fair value
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ (841,027) ​ ​ ​ ​ $ (166,562) ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ (594,699) ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Dividends or dividend equivalents
not otherwise included in total
compensation
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Total Adjustments for Equity
Awards
​ ​ ​ $ (1,584,584) ​ ​ ​ ​ $ (531,133) ​ ​ ​ ​ $ 1,756,733 ​ ​ ​ ​ $ (4,803,124) ​ ​ ​ ​ $ (1,211,051) ​ ​ ​ ​ $ (438,640) ​ ​ ​ ​ $ (144,169) ​ ​ ​ ​ $ (15,056,642) ​ ​ ​ ​ $ (3,816,390) ​ ​ ​ ​ $ 13,870,451 ​ ​ ​ ​ $ 4,132,402 ​ ​
Compensation Actually Paid (as calculated)
​ ​ ​ $ 29,170 ​ ​ ​ ​ $ 920,602 ​ ​ ​ ​ $ 4,357,982 ​ ​ ​ ​ $ (353,115) ​ ​ ​ ​ $ 495,789 ​ ​ ​ ​ $ 2,407,467 ​ ​ ​ ​ $ 1,079,403 ​ ​ ​ ​ $ (6,779,152) ​ ​ ​ ​ $ (1,407,347) ​ ​ ​ ​ $ 16,408,361 ​ ​ ​ ​ $ 6,137,850 ​ ​
(4)
Valuation assumptions used to calculate fair values as of vesting dates and fiscal year end did not materially differ from those used to calculate fair values at the time of grant as reflected in the Summary Compensation Table amounts, except that the volatility assumptions used to calculate fair values at date of vesting and fiscal year end are based solely on available volatility data for our common stock. Due to a lack of historical volatility data for our common stock, the expected volatility utilized for the purposes of calculating the grant date fair value was determined based on a blended rate of the historical volatility of our common stock combined with the historical volatility of comparable publicly traded companies. The other assumptions used in the valuation of equity awards are set forth in Note 10 to our financial statements included in our 2024 Annual Report. Compensation Actually Paid for 2020, 2021, 2022 and 2023 as reflected in our proxy statement for our 2024 annual meeting of stockholders has been adjusted to incorporate updated volatility assumptions.
​
(5)
Non-PEO NEOs reflect the average Summary Compensation Table total compensation and average CAP for the following executives by year:
​
•
2024: Mohan Bala, Ph.D., Alejandra Carvajal, Brian DeSchuytner, and Timothy B. Lowinger, Ph.D.
​
•
2023: Mohan Bala, Ph.D., Alejandra Carvajal, Brian DeSchuytner, Timothy B. Lowinger, Ph.D. and Arvin Yang, M.D., Ph.D.
​
•
2022: Alejandra Carvajal, Brian DeSchuytner, Timothy B. Lowinger, Ph.D. and Arvin Yang, M.D., Ph.D.
​
•
2021: Alejandra Carvajal, Brian DeSchuytner, Michael Kaufman, Ph.D., Timothy B. Lowinger, Ph.D. and Tushar Misra, Ph.D.
​
•
2020: Brian DeSchuytner, Michael Kaufman, Ph.D., Timothy B. Lowinger, Ph.D. and Arvin Yang, M.D., Ph.D.
​
(6)
The Peer Group Total Shareholder Return set forth in this table utilizes the NASDAQ Biotechnology Index, which we also utilize in the stock performance graph required by Item 201(e) of Regulation S-K included in our 2024 Annual Report. The comparison assumes $100 was invested for the period starting December 31, 2019, through the end of the listed year in the company and in the NASDAQ Biotechnology Index, respectively. Historical stock performance is not necessarily indicative of future stock performance.
       
Named Executive Officers, Footnote
•
2024: Mohan Bala, Ph.D., Alejandra Carvajal, Brian DeSchuytner, and Timothy B. Lowinger, Ph.D.
•
2023: Mohan Bala, Ph.D., Alejandra Carvajal, Brian DeSchuytner, Timothy B. Lowinger, Ph.D. and Arvin Yang, M.D.
•
2022: Alejandra Carvajal, Brian DeSchuytner, Timothy B. Lowinger, Ph.D. and Arvin Yang, M.D.
•
2021: Alejandra Carvajal, Brian DeSchuytner, Michael Kaufman, Ph.D., Timothy B. Lowinger, Ph.D. and Tushar Misra, Ph.
•
2020: Brian DeSchuytner, Michael Kaufman, Ph.D., Timothy B. Lowinger, Ph.D. and Arvin Yang, M.D.
Peer Group Issuers, Footnote
(6)
The Peer Group Total Shareholder Return set forth in this table utilizes the NASDAQ Biotechnology Index, which we also utilize in the stock performance graph required by Item 201(e) of Regulation S-K included in our 2024 Annual Report. The comparison assumes $100 was invested for the period starting December 31, 2019, through the end of the listed year in the company and in the NASDAQ Biotechnology Index, respectively. Historical stock performance is not necessarily indicative of future stock performance.
       
Adjustment To PEO Compensation, Footnote
(3)
The following tables describe deductions from, and additions to, total compensation in the Summary Compensation Table by year to calculate CAP. The Summary Compensation Table Amounts and CAP 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. Certain amounts reflected for fiscal year 2023 have been revised in select instances in order to incorporate administrative updates.
​
​ ​ ​
2024
​ ​
2023
​ ​
2022
​ ​
2021
​ ​
2020
​
​ ​ ​
First
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
First
PEO
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​
Total Compensation from Summary Compensation Table
​ ​ ​ $ 1,613,754 ​ ​ ​ ​ $ 1,451,735 ​ ​ ​ ​ $ 2,601,249 ​ ​ ​ ​ $ 4,450,009 ​ ​ ​ ​ $ 1,706,840 ​ ​ ​ ​ $ 2,846,107 ​ ​ ​ ​ $ 1,223,572 ​ ​ ​ ​ $ 8,277,490 ​ ​ ​ ​ $ 2,409,043 ​ ​ ​ ​ $ 2,537,911 ​ ​ ​ ​ $ 2,005,448 ​ ​
Adjustments for Pension ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Adjustment Summary Compensation Table Pension
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Amount added for current year service cost
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Amount added for prior service cost impacting current year
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Total Adjustments for Pension
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Adjustments for Equity Awards ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Adjustment for grant date values
in the Summary Compensation
Table
​ ​ ​ $ (651,679) ​ ​ ​ ​ $ (797,723) ​ ​ ​ ​ $ (2,013,740) ​ ​ ​ ​ $ (3,776,707) ​ ​ ​ ​ $ (1,141,206) ​ ​ ​ ​ $ (1,798,507) ​ ​ ​ ​ $ (553,715) ​ ​ ​ ​ $ (7,425,154) ​ ​ ​ ​ $ (1,981,419) ​ ​ ​ ​ $ (1,656,411) ​ ​ ​ ​ $ (1,550,241) ​ ​
Year-end fair value of unvested awards granted in the current year
​ ​ ​ $ 241,809 ​ ​ ​ ​ $ 296,000 ​ ​ ​ ​ $ 3,636,092 ​ ​ ​ ​ $ 510,197 ​ ​ ​ ​ $ 347,755 ​ ​ ​ ​ $ 1,441,729 ​ ​ ​ ​ $ 443,870 ​ ​ ​ ​ $ 1,538,348 ​ ​ ​ ​ $ 430,621 ​ ​ ​ ​ $ 7,965,820 ​ ​ ​ ​ $ 3,341,447 ​ ​
Year-over-year difference of
year-end fair values for unvested
awards granted in prior years
​ ​ ​ $ (1,041,598) ​ ​ ​ ​ $ (138,616) ​ ​ ​ ​ $ — ​ ​ ​ ​ $ (643,200) ​ ​ ​ ​ $ (220,779) ​ ​ ​ ​ $ (196,374) ​ ​ ​ ​ $ (58,449) ​ ​ ​ ​ $ (6,105,508) ​ ​ ​ ​ $ (1,108,788) ​ ​ ​ ​ $ 5,655,169 ​ ​ ​ ​ $ 1,717,834 ​ ​
Fair values at vest date for awards
granted and vested in current
year
​ ​ ​ $ 81,272 ​ ​ ​ ​ $ 99,487 ​ ​ ​ ​ $ 31,811 ​ ​ ​ ​ $ 229,104 ​ ​ ​ ​ $ 54,374 ​ ​ ​ ​ $ 226,105 ​ ​ ​ ​ $ 69,615 ​ ​ ​ ​ $ 567,422 ​ ​ ​ ​ $ 99,283 ​ ​ ​ ​ $ 822,260 ​ ​ ​ ​ $ 215,235 ​ ​
Difference in fair values between prior year-end fair values and vest date fair values for awards granted in prior years
​ ​ ​ $ (214,389) ​ ​ ​ ​ $ 9,719 ​ ​ ​ ​ $ 102,570 ​ ​ ​ ​ $ (281,491) ​ ​ ​ ​ $ (84,633) ​ ​ ​ ​ $ (111,593) ​ ​ ​ ​ $ (45,490) ​ ​ ​ ​ $ (3,631,751) ​ ​ ​ ​ $ (661,387) ​ ​ ​ ​ $ 1,083,613 ​ ​ ​ ​ $ 408,127 ​ ​
Forfeitures during current year equal to prior year-end fair value
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ (841,027) ​ ​ ​ ​ $ (166,562) ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ (594,699) ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Dividends or dividend equivalents
not otherwise included in total
compensation
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Total Adjustments for Equity
Awards
​ ​ ​ $ (1,584,584) ​ ​ ​ ​ $ (531,133) ​ ​ ​ ​ $ 1,756,733 ​ ​ ​ ​ $ (4,803,124) ​ ​ ​ ​ $ (1,211,051) ​ ​ ​ ​ $ (438,640) ​ ​ ​ ​ $ (144,169) ​ ​ ​ ​ $ (15,056,642) ​ ​ ​ ​ $ (3,816,390) ​ ​ ​ ​ $ 13,870,451 ​ ​ ​ ​ $ 4,132,402 ​ ​
Compensation Actually Paid (as calculated)
​ ​ ​ $ 29,170 ​ ​ ​ ​ $ 920,602 ​ ​ ​ ​ $ 4,357,982 ​ ​ ​ ​ $ (353,115) ​ ​ ​ ​ $ 495,789 ​ ​ ​ ​ $ 2,407,467 ​ ​ ​ ​ $ 1,079,403 ​ ​ ​ ​ $ (6,779,152) ​ ​ ​ ​ $ (1,407,347) ​ ​ ​ ​ $ 16,408,361 ​ ​ ​ ​ $ 6,137,850 ​ ​
       
Non-PEO NEO Average Total Compensation Amount $ 1,451,735 $ 1,706,840 $ 1,223,572 $ 2,409,043 $ 2,005,448
Non-PEO NEO Average Compensation Actually Paid Amount $ 920,602 495,789 1,079,403 (1,407,347) 6,137,850
Adjustment to Non-PEO NEO Compensation Footnote
(3)
The following tables describe deductions from, and additions to, total compensation in the Summary Compensation Table by year to calculate CAP. The Summary Compensation Table Amounts and CAP 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. Certain amounts reflected for fiscal year 2023 have been revised in select instances in order to incorporate administrative updates.
​
​ ​ ​
2024
​ ​
2023
​ ​
2022
​ ​
2021
​ ​
2020
​
​ ​ ​
First
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
First
PEO
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​ ​
Second
PEO
​ ​
Average
Non-PEO
NEOs
​
Total Compensation from Summary Compensation Table
​ ​ ​ $ 1,613,754 ​ ​ ​ ​ $ 1,451,735 ​ ​ ​ ​ $ 2,601,249 ​ ​ ​ ​ $ 4,450,009 ​ ​ ​ ​ $ 1,706,840 ​ ​ ​ ​ $ 2,846,107 ​ ​ ​ ​ $ 1,223,572 ​ ​ ​ ​ $ 8,277,490 ​ ​ ​ ​ $ 2,409,043 ​ ​ ​ ​ $ 2,537,911 ​ ​ ​ ​ $ 2,005,448 ​ ​
Adjustments for Pension ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Adjustment Summary Compensation Table Pension
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Amount added for current year service cost
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Amount added for prior service cost impacting current year
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Total Adjustments for Pension
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Adjustments for Equity Awards ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Adjustment for grant date values
in the Summary Compensation
Table
​ ​ ​ $ (651,679) ​ ​ ​ ​ $ (797,723) ​ ​ ​ ​ $ (2,013,740) ​ ​ ​ ​ $ (3,776,707) ​ ​ ​ ​ $ (1,141,206) ​ ​ ​ ​ $ (1,798,507) ​ ​ ​ ​ $ (553,715) ​ ​ ​ ​ $ (7,425,154) ​ ​ ​ ​ $ (1,981,419) ​ ​ ​ ​ $ (1,656,411) ​ ​ ​ ​ $ (1,550,241) ​ ​
Year-end fair value of unvested awards granted in the current year
​ ​ ​ $ 241,809 ​ ​ ​ ​ $ 296,000 ​ ​ ​ ​ $ 3,636,092 ​ ​ ​ ​ $ 510,197 ​ ​ ​ ​ $ 347,755 ​ ​ ​ ​ $ 1,441,729 ​ ​ ​ ​ $ 443,870 ​ ​ ​ ​ $ 1,538,348 ​ ​ ​ ​ $ 430,621 ​ ​ ​ ​ $ 7,965,820 ​ ​ ​ ​ $ 3,341,447 ​ ​
Year-over-year difference of
year-end fair values for unvested
awards granted in prior years
​ ​ ​ $ (1,041,598) ​ ​ ​ ​ $ (138,616) ​ ​ ​ ​ $ — ​ ​ ​ ​ $ (643,200) ​ ​ ​ ​ $ (220,779) ​ ​ ​ ​ $ (196,374) ​ ​ ​ ​ $ (58,449) ​ ​ ​ ​ $ (6,105,508) ​ ​ ​ ​ $ (1,108,788) ​ ​ ​ ​ $ 5,655,169 ​ ​ ​ ​ $ 1,717,834 ​ ​
Fair values at vest date for awards
granted and vested in current
year
​ ​ ​ $ 81,272 ​ ​ ​ ​ $ 99,487 ​ ​ ​ ​ $ 31,811 ​ ​ ​ ​ $ 229,104 ​ ​ ​ ​ $ 54,374 ​ ​ ​ ​ $ 226,105 ​ ​ ​ ​ $ 69,615 ​ ​ ​ ​ $ 567,422 ​ ​ ​ ​ $ 99,283 ​ ​ ​ ​ $ 822,260 ​ ​ ​ ​ $ 215,235 ​ ​
Difference in fair values between prior year-end fair values and vest date fair values for awards granted in prior years
​ ​ ​ $ (214,389) ​ ​ ​ ​ $ 9,719 ​ ​ ​ ​ $ 102,570 ​ ​ ​ ​ $ (281,491) ​ ​ ​ ​ $ (84,633) ​ ​ ​ ​ $ (111,593) ​ ​ ​ ​ $ (45,490) ​ ​ ​ ​ $ (3,631,751) ​ ​ ​ ​ $ (661,387) ​ ​ ​ ​ $ 1,083,613 ​ ​ ​ ​ $ 408,127 ​ ​
Forfeitures during current year equal to prior year-end fair value
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ (841,027) ​ ​ ​ ​ $ (166,562) ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ (594,699) ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Dividends or dividend equivalents
not otherwise included in total
compensation
​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​ ​ ​ $ — ​ ​
Total Adjustments for Equity
Awards
​ ​ ​ $ (1,584,584) ​ ​ ​ ​ $ (531,133) ​ ​ ​ ​ $ 1,756,733 ​ ​ ​ ​ $ (4,803,124) ​ ​ ​ ​ $ (1,211,051) ​ ​ ​ ​ $ (438,640) ​ ​ ​ ​ $ (144,169) ​ ​ ​ ​ $ (15,056,642) ​ ​ ​ ​ $ (3,816,390) ​ ​ ​ ​ $ 13,870,451 ​ ​ ​ ​ $ 4,132,402 ​ ​
Compensation Actually Paid (as calculated)
​ ​ ​ $ 29,170 ​ ​ ​ ​ $ 920,602 ​ ​ ​ ​ $ 4,357,982 ​ ​ ​ ​ $ (353,115) ​ ​ ​ ​ $ 495,789 ​ ​ ​ ​ $ 2,407,467 ​ ​ ​ ​ $ 1,079,403 ​ ​ ​ ​ $ (6,779,152) ​ ​ ​ ​ $ (1,407,347) ​ ​ ​ ​ $ 16,408,361 ​ ​ ​ ​ $ 6,137,850 ​ ​
       
Compensation Actually Paid vs. Total Shareholder Return [MISSING IMAGE: bc_tsr-4c.jpg]        
Compensation Actually Paid vs. Net Income [MISSING IMAGE: bc_netloss-4c.jpg]        
Total Shareholder Return Vs Peer Group [MISSING IMAGE: bc_tsr-4c.jpg]        
Total Shareholder Return Amount $ 24.96 40.49 102.27 108.55 464.4
Peer Group Total Shareholder Return Amount 118.2 118.87 113.65 126.45 126.42
Net Income (Loss) $ (69,200,000) (171,700,000) (204,200,000) (170,100,000) (88,000,000)
PEO Name Martin Huber, M.D.        
Martin Huber, M.D. [Member]          
Pay vs Performance Disclosure          
PEO Total Compensation Amount $ 1,613,754 2,601,249      
PEO Actually Paid Compensation Amount 29,170 4,357,982      
Anna Protopapas [Member]          
Pay vs Performance Disclosure          
PEO Total Compensation Amount   4,450,009 2,846,107 8,277,490 2,537,911
PEO Actually Paid Compensation Amount   (353,115) 2,407,467 (6,779,152) 16,408,361
PEO | Martin Huber, M.D. [Member] | Aggregate Pension Adjustments Service Cost          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount      
PEO | Martin Huber, M.D. [Member] | Pension Adjustments Service Cost          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount      
PEO | Martin Huber, M.D. [Member] | Pension Adjustments Prior Service Cost          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount      
PEO | Martin Huber, M.D. [Member] | Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount (651,679) (2,013,740)      
PEO | Martin Huber, M.D. [Member] | Equity Awards Adjustments, Excluding Value Reported in Compensation Table          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount (1,584,584) 1,756,733      
PEO | Martin Huber, M.D. [Member] | Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount 241,809 3,636,092      
PEO | Martin Huber, M.D. [Member] | Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount (1,041,598)      
PEO | Martin Huber, M.D. [Member] | Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount 81,272 31,811      
PEO | Martin Huber, M.D. [Member] | Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount (214,389) 102,570      
PEO | Martin Huber, M.D. [Member] | Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount      
PEO | Martin Huber, M.D. [Member] | Total Net Adjustments For Pension [Member]          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount      
PEO | Martin Huber, M.D. [Member] | Forfeitures During Current Year Equal To Prior Year-End Fair Value [Member]          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount      
PEO | Anna Protopapas [Member] | Aggregate Pension Adjustments Service Cost          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount  
PEO | Anna Protopapas [Member] | Pension Adjustments Service Cost          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount  
PEO | Anna Protopapas [Member] | Pension Adjustments Prior Service Cost          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount  
PEO | Anna Protopapas [Member] | Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount   (3,776,707) (1,798,507) (7,425,154) (1,656,411)
PEO | Anna Protopapas [Member] | Equity Awards Adjustments, Excluding Value Reported in Compensation Table          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount   (4,803,124) (438,640) (15,056,642) 13,870,451
PEO | Anna Protopapas [Member] | Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount   510,197 1,441,729 1,538,348 7,965,820
PEO | Anna Protopapas [Member] | Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount   (643,200) (196,374) (6,105,508) 5,655,169
PEO | Anna Protopapas [Member] | Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount   229,104 226,105 567,422 822,260
PEO | Anna Protopapas [Member] | Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount   (281,491) (111,593) (3,631,751) 1,083,613
PEO | Anna Protopapas [Member] | Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount  
PEO | Anna Protopapas [Member] | Total Net Adjustments For Pension [Member]          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount  
PEO | Anna Protopapas [Member] | Forfeitures During Current Year Equal To Prior Year-End Fair Value [Member]          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount   (841,027)
Non-PEO NEO | Aggregate Pension Adjustments Service Cost          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount
Non-PEO NEO | Pension Adjustments Service Cost          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount
Non-PEO NEO | Pension Adjustments Prior Service Cost          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount
Non-PEO NEO | Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount (797,723) (1,141,206) (553,715) (1,981,419) (1,550,241)
Non-PEO NEO | Equity Awards Adjustments, Excluding Value Reported in Compensation Table          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount (531,133) (1,211,051) (144,169) (3,816,390) 4,132,402
Non-PEO NEO | Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount 296,000 347,755 443,870 430,621 3,341,447
Non-PEO NEO | Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount (138,616) (220,779) (58,449) (1,108,788) 1,717,834
Non-PEO NEO | Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount 99,487 54,374 69,615 99,283 215,235
Non-PEO NEO | Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount 9,719 (84,633) (45,490) (661,387) 408,127
Non-PEO NEO | Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount
Non-PEO NEO | Total Net Adjustments For Pension [Member]          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount
Non-PEO NEO | Forfeitures During Current Year Equal To Prior Year-End Fair Value [Member]          
Pay vs Performance Disclosure          
Adjustment to Compensation, Amount $ (166,562) $ (594,699)