XML 35 R26.htm IDEA: XBRL DOCUMENT
v3.22.1

Note 10 - Stock-based Compensation (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2022
Notes Tables |
Share-Based Payment Arrangement, Option, Activity [Table Text Block] |
|  |  |  |  |  | Weighted- |
|  |  |  |  |  | Average |
|  | Stock Options |  |  | Exercise Price |
Options outstanding at December 31, 2021 |  |  | 233,384 |  |  | $ | 97.78 |
Granted |  |  | 52,992 |  |  |  | 59.40 |
Exercised |  |  | (201 | ) |  |  | 30.58 |
Forfeited |  |  | (21,287 | ) |  |  | 86.55 |
Options outstanding at March 31, 2022 |  |  | 264,888 |  |  | $ | 91.06 |
Exercisable at March 31, 2022 |  |  | 126,595 |  |  | $ | 87.42 |
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] |
|  | Three Months Ended March 31, |
|  | 2022 |  |  | 2021 |
Risk-free interest rate |  |  | 1.94% |  |  |  | 0.80% - 0.96% |
Expected life (years) |  |  | 6.25 |  |  |  | 6.25 |
Expected volatility |  |  | 45.95% |  |  |  | 45.28 - 45.35% |
Expected dividend yield |  |  | 0% |  |  |  | 0% |
Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] |
|  |  |  |  |  | Weighted- |
|  |  |  |  |  | Average |
|  |  |  |  |  | Grant Date |
|  | Restricted |  |  | Fair Value |
|  | Stock |  |  | Per Share |
Restricted stock at December 31, 2021 |  |  | 343,782 |  |  | $ | 111.79 |
Granted |  |  | 44,782 |  |  |  | 59.40 |
Restrictions lapsed |  |  | (35,207 | ) |  |  | 123.15 |
Forfeited |  |  | (11,068 | ) |  |  | 109.73 |
Restricted stock at March 31, 2022 |  |  | 342,289 |  |  | $ | 103.84 |
Schedule of Nonvested Performance-Based Units Activity [Table Text Block] |
|  |  |  |  |  | Weighted- |
|  |  |  |  |  | Average |
|  |  |  |  |  | Grant Date |
|  | Performance |  |  | Fair Value |
|  | Stock |  |  | Per Share |
Performance stock at December 31, 2021 |  |  | 16,839 |  |  | $ | 115.56 |
Granted |  |  | 32,620 |  |  |  | 100.33 |
Restrictions lapsed |  |  | - |  |  |  | - |
Performance change |  |  | - |  |  |  | - |
Forfeited |  |  | - |  |  |  | - |
Performance stock at March 31, 2022 |  |  | 49,459 |  |  | $ | 105.52 |
Schedule of Share-based Payment Award, Awards Other Than Stock Options, Valuation Assumptions [Table Text Block] |
|  | Three Months Ended March 31, |
|  | 2022 |  |  | 2021 |
Risk-free interest rate |  |  | 1.76% |  |  |  | 0.22% |
Expected life (years) |  |  | 2.87 |  |  |  | 2.87 |
Expected volatility |  |  | 53.50% |  |  |  | 51.40% |
Expected dividend yield |  |  | 0% |  |  |  | 0% |
Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block] |
|  | Three Months Ended March 31, |
|  | 2022 |  |  | 2021 |
Risk-free interest rate |  |  | 0.17% |  |  |  | 0.12% |
Expected life (months) |  |  | 6.00 |  |  |  | 6.00 |
Expected volatility |  |  | 53.44% |  |  |  | 50.85% |
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
- Definition Tabular disclosure of the changes in outstanding nonvested performance-based units. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901 + 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 -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e) -URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901 + 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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2) -URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901 + 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 -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2) -URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901 + 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 No definition available. + Details
Name: | us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

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