XML 27 R16.htm IDEA: XBRL DOCUMENT v3.24.2.u1
Stock-based Compensation
 6 Months Ended
Jun. 30, 2024
Share-Based Payment Arrangement [Abstract]  
Stock-based Compensation Stock-based Compensation
Employee Stock Purchase Plan
In April 2023, the Board approved an employee stock purchase plan (the “ESPP”) which became effective upon approval at the Annual Meeting in June 2023. The ESPP allows eligible employees of the Company to purchase shares of our common stock through payroll deductions. Offering periods are generally over a 24-month period and begin in May and November of each year. The per share purchase price will be the lower of 85% of the closing trading price per share of our common stock on the first trading date of an offering period in which a participant is enrolled or 85% of the closing trading price per share on the purchase date. Participant purchases are limited to a maximum of $25,000 of fair value of our stock per calendar year. The Company is authorized to grant up to 2,000,000 shares of common stock under the ESPP. The first offering period of the ESPP commenced in December 2023. For the three and six months ended June 30, 2024, 123,889 shares of common stock were purchased under the ESPP. As of June 30, 2024, 1,876,111 shares of common stock were available for future issuance under the ESPP.
We recognized $72 thousand and $149 thousand of stock-based compensation expenses related to the ESPP for the three and six months ended June 30, 2024, respectively. As of June 30, 2024, the total unrecognized stock-based compensation expense, net of expected forfeitures, related to the ESPP was $0.6 million and is expected to be recognized over the remaining offering period.
Stock Options
Stock options granted to employees generally have a maximum term of ten years and vest over four years from the date of grant, of which 25% vest at the end of one year, and 75% vest monthly over the remaining three years. In January 2024, the Board approved the grants of stock options with a vesting term over three years from the date of grant, of which 33% vest at the end of one year, and 67% vest monthly over the remaining two years.
Restricted Stock Units (“RSUs”)
We also grant employees RSUs, which generally vest over either a period with 33% of the shares subject to the RSUs vesting on each yearly anniversary of the vesting commencement date, in each case contingent upon such employee’s continued service on such vesting date. We may grant RSUs with different vesting terms from time to time.
Stock-Based Compensation Expense
Stock-based compensation expense is included in the unaudited condensed consolidated statements of operations as follows (in thousands):
 Three Months Ended June 30,Six Months Ended June 30,
 2024202320242023
Cost of product revenue$101 $83 $216 $212 
Research and development 641 806 1,461 1,528 
Selling, general and administrative3,940 1,827 6,176 3,785 
Total$4,682 $2,716 $7,853 $5,525 
The following table presents total stock-based compensation expense by security type included in the unaudited condensed consolidated statements of operations (in thousands):
 Three Months Ended June 30,Six Months Ended June 30,
 2024202320242023
Stock options$2,117 $1,096 $3,631 $2,018 
RSUs and restricted stock awards (“RSAs”)
1,152 1,373 2,469 2,499 
Performance-contingent restricted stock units (“PSUs”)
— 279 247 1,116 
Performance based options (“PBOs”)
1,341 (32)1,357 (108)
ESPP72 — 149 — 
Total$4,682 $2,716 $7,853 $5,525 
On June 29, 2024, we entered into an Advisory Services Agreement with a former executive of the Company. Pursuant to the advisory agreement, the exercise period for the former executive’s vested stock options and performance-based options was also extended. The modification resulted in a stock-based compensation expense of $2.0 million recognized in selling, general and administrative expenses for the three and six months ended June 30, 2024.
As of June 30, 2024, unrecognized stock-based compensation expense, net of expected forfeitures, was $12.0 million related to unvested stock options, and $6.0 million related to unvested RSUs and RSAs. Stock-based compensation expense for these awards will be recognized through 2028.