| Cover | 12 Months Ended |
| Dec. 31, 2022 | |
| Document Information [Line Items] | |
| Document Type | DEF 14A |
| Amendment Flag | false |
| Entity Information [Line Items] | |
| Entity Registrant Name | QUALYS, INC. |
| Entity Central Index Key | 0001107843 |
| Pay vs Performance Disclosure - USD ($) | 12 Months Ended | ||
| Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | |
| Pay vs Performance Disclosure [Table] | |||
| Pay vs Performance [Table Text Block] | Pay Versus Performance Disclosure Year Summary 1, 2 Compensation 1,3 Summary 1,2 Compensation 1,3 Average 4 Average 5 Value of Initial Fixed $100 Net Income 8 Revenues 9 Total 6 Peer Group 7 (a) (b) (c) (d) (e) (f) (g) (h) (i) (j) (k) 2022 — — $11,392,553 $5,138,863 $4,444,562 $2,529,882 $146.18 $149.98 $109,418,000 $489,723,000 2021 $20,875,111 $16,450,909 $9,396,664 $12,827,121 $4,140,001 $5,326,529 $164.59 $206.76 $70,960,000 $411,172,000 2020 $22,398,351 $30,358,397 — — $4,516,347 $5,326,614 $134.62 $132.79 $91,572,000 $362,963,000 (1) The first PEO is Philippe F. Courtot, who served as PEO in 2020 and in 2021 t hrough March 19, 2021. The s (2) Represents the total compensation paid to our PEO in each listed year, as shown in our Summary Compensation Table for (3) Compensation actually paid does not mean that our PEOs were actually paid those amounts in the listed year, but this is a dollar amount derived by adjusting the Summary Compensation Table total compensation under the methodology prescribed under the relevant rules, as shown in the following tables: First PEO 2020 2021 2022 Summary Compensation Table Total 22,398,351 20,875,111 — Subtract (21,560,357) — — Add Year-End 20,875,692 — — Adjust for 6,761,019 — — Adjust for — — — Adjust for Change in Fair Value as of Vesting Date of Option Awards and Stock Awards Granted in Prior Fiscal Years For Which Applicable Vesting Conditions Were Satisfied During Fiscal Year 1,883,692 343,840 — Subtract Year-End — (4,768,042) — Add Value of Dividends or other Earnings Paid on Stock or Option Awards not Otherwise Reflected in Fair Value or Total Compensation — — — Compensation Actually Paid 30,358,397 16,450,909 — Second PEO 2020 2021 2022 Summary Compensation Table Total — 9,396,664 11,392,553 Subtract — (8,364,620) (10,361,307) Add Year-End — 10,149,237 7,236,431 Adjust for — 1,821,938 (2,774,012) Adjust for — 136,595 - Adjust for — (312,693) (354,802) 2020 2021 2022 Subtract Year-End — — — Add Value of Dividends or other Earnings Paid on Stock or Option Awards not Otherwise Reflected in Fair Value or Total Compensation — — — Compensation Actually Paid — 12,827,121 5,138,863 (4) This figure is the average of the total compensation paid to our NEOs other than our PEO in each listed year, as shown in our Summary Compensation Table for such listed year. The names of the non-PEO 2020* 2021 2022 Thakar, Sumedh S. Kim, Joo Mi Kim, Joo Mi Kim, Joo Mi Posey, Bruce K. Posey, Bruce K. Posey, Bruce K. Peters, Allan Peters, Allan Fisher, Melissa B. *Melissa B. Fisher served as CFO through May 29, 2020, Joo Mi Kim served as CFO beginning on June 29, 2020 and in 2021, 2022. (5) This figure is the average of compensation actually paid for our NEOs other than our PEO in each listed year. Compensation actually paid does not mean that these NEOs were actually paid those amounts in the listed year, but this is a dollar amount derived by adjusting the average of the Summary Compensation Table total compensation figure for all NEOs other than our PEO for the listed year under the methodology prescribed under the SEC’s rules, as shown in the following table: Non-PEO 2020 2021 2022 Summary Compensation Table Total 4,516,347 4,140,001 4,444,562 Subtract (4,120,883) (3,625,418) (3,952,633) Add Year-End 4,849,573 4,474,781 2,907,240 Adjust for 1,598,905 415,872 (782,777) Adjust for 57,756 — — Adjust for 514,690 (78,707) (86,511) Subtract Year-End (2,089,773) — — Add Value of Dividends or other Earnings Paid on Stock or Option Awards not Otherwise Reflected in Fair Value or Total Compensation — — — Compensation Actually Paid 5,326,614 5,326,529 2,529,882 (6) Total shareholder return is calculated by assuming that a $100 investment was made on the day prior to the first fiscal year reported and reinvesting all dividends until the last day of each reported fiscal year. (7) The peer group used is the NASDAQ Computer Index, as used in the Company’s performance graph in our annual report. Total shareholder return is calculated by assuming that a $100 investment was made on the day prior to the first fiscal year reported below and reinvesting all dividends until the last day of each reported fiscal year. (8) The dollar amounts reported are the Company’s net income reflected in the Company’s audited financial statements for the reported fiscal year. (9) In the Company’s assessment, revenues is the financial performance measure that is the most important financial performance measure used by the Company in 2022 to link compensation actually paid to performance. | ||
| Company Selected Measure Name | revenues | ||
| Named Executive Officers, Footnote [Text Block] | (4) This figure is the average of the total compensation paid to our NEOs other than our PEO in each listed year, as shown in our Summary Compensation Table for such listed year. The names of the non-PEO 2020* 2021 2022 Thakar, Sumedh S. Kim, Joo Mi Kim, Joo Mi Kim, Joo Mi Posey, Bruce K. Posey, Bruce K. Posey, Bruce K. Peters, Allan Peters, Allan Fisher, Melissa B. *Melissa B. Fisher served as CFO through May 29, 2020, Joo Mi Kim served as CFO beginning on June 29, 2020 and in 2021, 2022. | ||
| Peer Group Issuers, Footnote [Text Block] | The peer group used is the NASDAQ Computer Index, as used in the Company’s performance graph in our annual report. Total shareholder return is calculated by assuming that a $100 investment was made on the day prior to the first fiscal year reported below and reinvesting all dividends until the last day of each reported fiscal year. | ||
| Adjustment To PEO Compensation, Footnote [Text Block] | (3) Compensation actually paid does not mean that our PEOs were actually paid those amounts in the listed year, but this is a dollar amount derived by adjusting the Summary Compensation Table total compensation under the methodology prescribed under the relevant rules, as shown in the following tables: First PEO 2020 2021 2022 Summary Compensation Table Total 22,398,351 20,875,111 — Subtract (21,560,357) — — Add Year-End 20,875,692 — — Adjust for 6,761,019 — — Adjust for — — — Adjust for Change in Fair Value as of Vesting Date of Option Awards and Stock Awards Granted in Prior Fiscal Years For Which Applicable Vesting Conditions Were Satisfied During Fiscal Year 1,883,692 343,840 — Subtract Year-End — (4,768,042) — Add Value of Dividends or other Earnings Paid on Stock or Option Awards not Otherwise Reflected in Fair Value or Total Compensation — — — Compensation Actually Paid 30,358,397 16,450,909 — Second PEO 2020 2021 2022 Summary Compensation Table Total — 9,396,664 11,392,553 Subtract — (8,364,620) (10,361,307) Add Year-End — 10,149,237 7,236,431 Adjust for — 1,821,938 (2,774,012) Adjust for — 136,595 - Adjust for — (312,693) (354,802) 2020 2021 2022 Subtract Year-End — — — Add Value of Dividends or other Earnings Paid on Stock or Option Awards not Otherwise Reflected in Fair Value or Total Compensation — — — Compensation Actually Paid — 12,827,121 5,138,863 | ||
| Non-PEO NEO Average Total Compensation Amount | $ 4,444,562 | $ 4,140,001 | $ 4,516,347 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 2,529,882 | 5,326,529 | 5,326,614 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | (5) This figure is the average of compensation actually paid for our NEOs other than our PEO in each listed year. Compensation actually paid does not mean that these NEOs were actually paid those amounts in the listed year, but this is a dollar amount derived by adjusting the average of the Summary Compensation Table total compensation figure for all NEOs other than our PEO for the listed year under the methodology prescribed under the SEC’s rules, as shown in the following table: Non-PEO 2020 2021 2022 Summary Compensation Table Total 4,516,347 4,140,001 4,444,562 Subtract (4,120,883) (3,625,418) (3,952,633) Add Year-End 4,849,573 4,474,781 2,907,240 Adjust for 1,598,905 415,872 (782,777) Adjust for 57,756 — — Adjust for 514,690 (78,707) (86,511) Subtract Year-End (2,089,773) — — Add Value of Dividends or other Earnings Paid on Stock or Option Awards not Otherwise Reflected in Fair Value or Total Compensation — — — Compensation Actually Paid 5,326,614 5,326,529 2,529,882 | ||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | Compensation Actually Paid The following chart reflects the amount of compensation actually paid to Mr. Thakar (for 2022 and 2021), Mr. Courtot (for 2021 and 2020), and the average amount of compensation actually paid to our NEOs as a group (excluding the PEOs in each given year) in relation to our company’s and our peer group’s TSR over the three years presented in the table: | ||
| Compensation Actually Paid vs. Net Income [Text Block] | Compensation Actually Paid and Net Income The following chart reflects the amount of compensation actually paid to Mr. Thakar (for 2022 and 2021), Mr. Courtot (for 2021 and 2020), and the average amount of compensation actually paid to our NEOs as a group (excluding the PEOs in each given year) in relation to the Company’s net income over the three years presented in the table: | ||
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | Compensation Actually Paid The following chart reflects the amount of compensation actually paid to Mr. Thakar (for 2022 and 2021), Mr. Courtot (for 2021 and 2020), and the average amount of compensation actually paid to our NEOs as a group (excluding the PEOs in each given year) in relation to the Company’s revenues over the three years presented in the table. While we utilize a number of performance measures to evaluate company performance, we have determined that revenues is the most important performance measure (not otherwise required to be disclosed in the table) to link compensation actually paid to the our NEOs to company performance. We utilize revenue growth when setting goals for our corporate bonus plan and PRSUs granted to our NEOs. | ||
| Total Shareholder Return Vs Peer Group [Text Block] | Compensation Actually Paid The following chart reflects the amount of compensation actually paid to Mr. Thakar (for 2022 and 2021), Mr. Courtot (for 2021 and 2020), and the average amount of compensation actually paid to our NEOs as a group (excluding the PEOs in each given year) in relation to our company’s and our peer group’s TSR over the three years presented in the table: | ||
| Tabular List [Table Text Block] | The list below includes the four financial performance measures that, in our assessment and in no particular order, represent the most important measures used to link compensation actually paid to our NEOs to company performance. Most Important Performance Measures Bookings Revenues Adjusted EBITDA Margin Non-GAAP | ||
| Total Shareholder Return Amount | $ 146.18 | 164.59 | 134.62 |
| Peer Group Total Shareholder Return Amount | 149.98 | 206.76 | 132.79 |
| Net Income (Loss) | $ 109,418,000,000,000 | $ 70,960,000,000,000 | $ 91,572,000,000,000 |
| Company Selected Measure Amount | 489,723,000 | 411,172,000 | 362,963,000 |
| PEO Name | Sumedh S. Thakar | Philippe F. Courtot | |
| Measure [Axis]: 1 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Bookings | ||
| Measure [Axis]: 2 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Revenues | ||
| Measure [Axis]: 3 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Adjusted EBITDA Margin | ||
| Measure [Axis]: 4 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Non-GAAP Earnings per Diluted Share | ||
| Philippe F. Courtot [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| PEO Total Compensation Amount | $ 0 | $ 20,875,111 | $ 22,398,351 |
| PEO Actually Paid Compensation Amount | 0 | 16,450,909 | 30,358,397 |
| Sumedh S. Thakar [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| PEO Total Compensation Amount | 11,392,553 | 9,396,664 | 0 |
| PEO Actually Paid Compensation Amount | 5,138,863 | 12,827,121 | 0 |
| PEO [Member] | Philippe F. Courtot [Member] | Grant Date Fair Value of Option Awards and Stock Awards Granted in Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | (21,560,357) |
| PEO [Member] | Philippe F. Courtot [Member] | Fair Value at Fiscal YearEnd of Outstanding and Unvested Option Awards and Stock Awards Granted in Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 20,875,692 |
| PEO [Member] | Philippe F. Courtot [Member] | Change in Fair Value of Outstanding and Unvested Option Awards and Stock Awards Granted in Prior Fiscal Years [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 6,761,019 |
| PEO [Member] | Philippe F. Courtot [Member] | Fair Value at Vesting of Option Awards and Stock Awards Granted in Fiscal Year That Vested During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Philippe F. Courtot [Member] | Change in Fair Value as of Vesting Date of Option Awards and Stock Awards Granted in Prior Fiscal Years For Which Applicable Vesting Conditions Were Satisfied During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 343,840 | 1,883,692 |
| PEO [Member] | Philippe F. Courtot [Member] | Fair Value as of Prior Fiscal YearEnd of Option Awards and Stock Awards Granted in Prior Fiscal Years That Failed to Meet Applicable Vesting Conditions During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | (4,768,042) | 0 |
| PEO [Member] | Philippe F. Courtot [Member] | Value of Dividends or other Earnings Paid on Stock or Option Awards not Otherwise Reflected in Fair Value or Total Compensation [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Sumedh S. Thakar [Member] | Grant Date Fair Value of Option Awards and Stock Awards Granted in Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (10,361,307) | (8,364,620) | 0 |
| PEO [Member] | Sumedh S. Thakar [Member] | Fair Value at Fiscal YearEnd of Outstanding and Unvested Option Awards and Stock Awards Granted in Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 7,236,431 | 10,149,237 | 0 |
| PEO [Member] | Sumedh S. Thakar [Member] | Change in Fair Value of Outstanding and Unvested Option Awards and Stock Awards Granted in Prior Fiscal Years [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (2,774,012) | 1,821,938 | 0 |
| PEO [Member] | Sumedh S. Thakar [Member] | Fair Value at Vesting of Option Awards and Stock Awards Granted in Fiscal Year That Vested During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 136,595 | 0 |
| PEO [Member] | Sumedh S. Thakar [Member] | Change in Fair Value as of Vesting Date of Option Awards and Stock Awards Granted in Prior Fiscal Years For Which Applicable Vesting Conditions Were Satisfied During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (354,802) | (312,693) | 0 |
| PEO [Member] | Sumedh S. Thakar [Member] | Fair Value as of Prior Fiscal YearEnd of Option Awards and Stock Awards Granted in Prior Fiscal Years That Failed to Meet Applicable Vesting Conditions During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Sumedh S. Thakar [Member] | Value of Dividends or other Earnings Paid on Stock or Option Awards not Otherwise Reflected in Fair Value or Total Compensation [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | Grant Date Fair Value of Option Awards and Stock Awards Granted in Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (3,952,633) | (3,625,418) | (4,120,883) |
| Non-PEO NEO [Member] | Fair Value at Fiscal YearEnd of Outstanding and Unvested Option Awards and Stock Awards Granted in Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 2,907,240 | 4,474,781 | 4,849,573 |
| Non-PEO NEO [Member] | Change in Fair Value of Outstanding and Unvested Option Awards and Stock Awards Granted in Prior Fiscal Years [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (782,777) | 415,872 | 1,598,905 |
| Non-PEO NEO [Member] | Fair Value at Vesting of Option Awards and Stock Awards Granted in Fiscal Year That Vested During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 57,756 |
| Non-PEO NEO [Member] | Change in Fair Value as of Vesting Date of Option Awards and Stock Awards Granted in Prior Fiscal Years For Which Applicable Vesting Conditions Were Satisfied During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (86,511) | (78,707) | 514,690 |
| Non-PEO NEO [Member] | Fair Value as of Prior Fiscal YearEnd of Option Awards and Stock Awards Granted in Prior Fiscal Years That Failed to Meet Applicable Vesting Conditions During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | (2,089,773) |
| Non-PEO NEO [Member] | Value of Dividends or other Earnings Paid on Stock or Option Awards not Otherwise Reflected in Fair Value or Total Compensation [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ 0 | $ 0 | $ 0 |
