XML 35 R25.htm IDEA: XBRL DOCUMENT
v3.25.2

Stock-Based Compensation (Tables) | 6 Months Ended
--- | ---
Jun. 30, 2025
Share-Based Payment Arrangement [Abstract] |
Schedule of Share-Based Payment Arrangement, Option, Activity | The following table summarizes stock option activity during the six months ended June 30, 2025:
| Stock Options |  | Weighted- Average Exercise Price
Options outstanding at December 31, 2024 | 445,136 |  | $ | 51.34 |
Granted | 139,872 |  | 39.32 |
Exercised | (8,762) |  | 33.77 |
Forfeited | (93,350) |  | 37.31 |
Expired | (16,354) |  | 87.74 |
Options outstanding at June 30, 2025 | 466,542 |  | $ | 49.60 |
Exercisable at June 30, 2025 | 254,268 |  | $ | 60.44 |
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions | The following table provides the assumptions used in the Black-Scholes pricing model valuation of options during the six months ended June 30, 2025 and 2024:
| Six Months Ended June 30,
| 2025 |  | 2024
Risk-free interest rate | 4.13% - 4.17% |  | 4.28% - 4.30%
Expected life (years) | 6.25 |  | 6.25
Expected volatility | 52.12% - 52.99% |  | 50.62% - 50.72%
Expected dividend yield | 0% |  | 0%
Schedule of Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity | The following table summarizes restricted stock units activity during the six months ended June 30, 2025:
| Restricted Stock Units |  | Weighted- Average Grant Date Fair Value Per Share
Restricted stock units at December 31, 2024 | 763,261 |  | $ | 38.25 |
Granted | 278,500 |  | 39.95 |
Restrictions lapsed | (212,421) |  | 40.55 |
Forfeited | (85,562) |  | 36.57 |
Restricted stock units at June 30, 2025 | 743,778 |  | $ | 38.42 |
Schedule of Nonvested Performance-Based Units Activity | The following table summarizes performance stock units activity during the six months ended June 30, 2025:
| Performance Stock Units |  | Weighted- Average Grant Date Fair Value Per Share
Performance stock units at December 31, 2024 | 180,173 |  | $ | 60.75 |
Granted 1 | 153,503 |  | 59.71 |
Restrictions lapsed | (32,977) |  | 96.41
Performance change | — |  | — |
Forfeited | (68,887) |  | 57
Performance stock units at June 30, 2025 | 231,812 |  | $ | 56.17 |
1 Includes a target number of 54,320 PSUs granted as part of the May 23, 2025, Inducement Awards, 27,160 of which have the same market condition as the PSUs granted under the 2022 Plan as described above, and 27,160 of which also include a performance condition with anywhere between 0 percent and 100 percent of the target number capable of being achieved during two six-month performance periods and then anywhere between 0 percent and 200 percent of such achieved PSUs capable of being earned and vesting during a three-year performance period depending on the Company's performance in the final year of the performance period and the award recipient's continued employment.
Schedule of Share-based Payment Award, Awards Other Than Stock Options, Valuation Assumptions | The following table provides the assumptions used in the Monte Carlo pricing model valuation of PSUs during the six months ended June 30, 2025 and 2024:
| Six Months Ended June 30,
| 2025 |  | 2024
Risk-free interest rate | 3.98% - 4.08% |  | 4.37%
Expected life (years) | 2.61 - 2.85 |  | 2.88
Expected volatility | 52.40% - 53.20% |  | 51.40%
Expected dividend yield | 0% |  | 0%
Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions | The following table presents the assumptions used to estimate the fair value of the ESPP during the six months ended June 30, 2025 and 2024:
| Six Months Ended June 30,
| 2025 |  | 2024
Risk-free interest rate | 4.29% |  | 5.07% - 5.16%
Expected life (months) | 6.00 |  | 6.00
Expected volatility | 65.60% |  | 30.97% - 47.92%
Expected dividend yield | 0% |  | 0%

X
- Definition Tabular disclosure of the valuation assumptions of share-based payment awards other than stock options. + References No definition available. + Details
Name: | prlb_ScheduleOfSharebasedPaymentAwardAwardsOtherThanStockOptionsValuationAssumptionsTableTextBlock
Namespace Prefix: | prlb_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the changes in outstanding nonvested performance-based units. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_ScheduleOfNonvestedPerformanceBasedUnitsActivityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d) -SubTopic 10 -Topic 718 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (e) -SubTopic 10 -Topic 718 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of employee stock purchase plans, including, but not limited to: (a) expected term, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 718 -SubTopic 50 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org/718-50/tableOfContent Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 718 -SubTopic 10 -Subparagraph (f)(2) -Name Accounting Standards Codification -Paragraph 2 -Section 50 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_ScheduleOfShareBasedPaymentAwardEmployeeStockPurchasePlanValuationAssumptionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 718 -SubTopic 10 -Subparagraph (f)(2) -Name Accounting Standards Codification -Paragraph 2 -Section 50 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Disclosure of the number and weighted-average grant date fair value for restricted stock and restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock and restricted stock units that were granted, vested, or forfeited during the year. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration