| 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 | Guardant Health, Inc. |
| Entity Central Index Key | 0001576280 |
| Pay vs Performance Disclosure - USD ($) | 12 Months Ended | ||
| Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | |
| Pay vs Performance Disclosure [Table] | |||
| Pay vs Performance [Table Text Block] | Pay Versus Performance In accordance with rules adopted by the Securities and Exchange Commission pursuan Non-PEO Year Summary Summary Compensation (1) (2) (3) Compensation (1) (2) (3) Average Non-PEO Average Non-PEO (1) (2) (3) Value of Initial Net Income Revenue (5) ($ Millions) TSR Peer (a) (b) (b) (c) (c) (d) (e) (f) (g) (h) (i) 2022 11,632 11,175 (68,726,853) (68,727,310) 3,895,818 538,306 39.25 113.65 (654.6) 449.5 2021 13,665 13,271 (30,979,967) (30,980,361) 5,016,617 3,923,973 156.16 126.45 (384.8) 373.7 2020 113,870,986 — 196,429,143 — 29,791,305 51,705,986 201.22 126.42 (246.3) 286.7 (1) Helmy Eltoukhy and AmirAli Talasaz were our PEOs in 2021 and 2022. Helmy Eltoukhy was our PEO in 2020. The individuals comprising the Non-PEO 2020 2021 2022 AmirAli Talasaz Michael Bell Michael Bell Derek Bertocci Craig Eagle Craig Eagle Michael Wiley Christopher Freeman Christopher Freeman John Saia John Saia John Saia (2) The amounts shown for Compensation Actually Paid have been calculated in accordance with Item 402(v) of Regulation S-K (3) Compensation Actually Paid reflects the exclusions and inclusions of certain amounts for the PEOs and the Non-PEO Year Summary Compensation Exclusion of Stock Inclusion of Equity Compensation Actually 2022 11,632 — (68,738,485) (68,726,853) 2021 13,665 — (30,993,632) (30,979,967) 2020 113,870,986 (113,595,323) 196,153,480 196,429,143 Year Summary Compensation Exclusion of Stock Inclusion of Equity Compensation Actually 2022 11,175 — (68,738,485) (68,727,310) 2021 13,271 (14,375,350) (30,993,632) (30,980,361) Year Average Summary Non-PEO Average Exclusion of Non-PEO Average Inclusion of Non-PEO Average Compensation Non-PEO 2022 3,895,818 (3,261,391) (96,121) 538,306 2021 5,016,617 (3,651,612) 2,558,968 3,923,973 2020 29,791,305 (29,326,181) 51,240,862 51,705,986 The amounts in the Inclusion of Equity Values in the tables above are derived from the amounts set forth in the following tables: Year Year-End Change in Fair Vesting-Date Fair Change in Fair Fair Value at Total - 2022 — (68,738,485) — — — (68,738,485) 2021 — (33,636,991) — 2,643,359 — (30,993,632) 2020 186,645,071 5,021,606 — 4,486,803 — 196,153,480 Year Year-End Change in Fair Vesting-Date Fair Change in Fair Fair Value at Total - 2022 — (68,738,485) — — — (68,738,485) 2021 — (33,636,991) — 2,643,359 — (30,993,632) Year Average Year-End Non-PEO Average Change in Non-PEO Average Vesting- Non-PEO Average Change Non-PEO Average Fair Non-PEO Total - Non-PEO 2022 1,995,203 (1,584,218) — (507,106) — (96,121) 2021 2,728,176 (197,657) — 28,449 — 2,558,968 2020 48,075,762 1,860,798 — 1,304,302 — 51,240,862 (4) The Peer Group TSR 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 (5) We determined revenue to be the most important financial performance measure used to link Company performance to Compensation Actually Paid to our Non-PEO | ||
| Company Selected Measure Name | Revenue | ||
| Named Executive Officers, Footnote [Text Block] | 2020 2021 2022 AmirAli Talasaz Michael Bell Michael Bell Derek Bertocci Craig Eagle Craig Eagle Michael Wiley Christopher Freeman Christopher Freeman John Saia John Saia John Saia | ||
| Peer Group Issuers, Footnote [Text Block] | The Peer Group TSR 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 | ||
| Adjustment To PEO Compensation, Footnote [Text Block] | Year Summary Compensation Exclusion of Stock Inclusion of Equity Compensation Actually 2022 11,632 — (68,738,485) (68,726,853) 2021 13,665 — (30,993,632) (30,979,967) 2020 113,870,986 (113,595,323) 196,153,480 196,429,143 Year Summary Compensation Exclusion of Stock Inclusion of Equity Compensation Actually 2022 11,175 — (68,738,485) (68,727,310) 2021 13,271 (14,375,350) (30,993,632) (30,980,361) Year Year-End Change in Fair Vesting-Date Fair Change in Fair Fair Value at Total - 2022 — (68,738,485) — — — (68,738,485) 2021 — (33,636,991) — 2,643,359 — (30,993,632) 2020 186,645,071 5,021,606 — 4,486,803 — 196,153,480 Year Year-End Change in Fair Vesting-Date Fair Change in Fair Fair Value at Total - 2022 — (68,738,485) — — — (68,738,485) 2021 — (33,636,991) — 2,643,359 — (30,993,632) | ||
| Non-PEO NEO Average Total Compensation Amount | $ 3,895,818 | $ 5,016,617 | $ 29,791,305 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 538,306 | 3,923,973 | 51,705,986 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | Year Average Summary Non-PEO Average Exclusion of Non-PEO Average Inclusion of Non-PEO Average Compensation Non-PEO 2022 3,895,818 (3,261,391) (96,121) 538,306 2021 5,016,617 (3,651,612) 2,558,968 3,923,973 2020 29,791,305 (29,326,181) 51,240,862 51,705,986 Year Average Year-End Non-PEO Average Change in Non-PEO Average Vesting- Non-PEO Average Change Non-PEO Average Fair Non-PEO Total - Non-PEO 2022 1,995,203 (1,584,218) — (507,106) — (96,121) 2021 2,728,176 (197,657) — 28,449 — 2,558,968 2020 48,075,762 1,860,798 — 1,304,302 — 51,240,862 | ||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | Description of Relationship Between PEO and Non-PEO The following chart sets forth the relationship between Compensation Actually Paid to our PEOs, the average of Compensation Actually Paid to our Non-PEO | ||
| Compensation Actually Paid vs. Net Income [Text Block] | Description of Relationship Between PEO and Non-PEO The following chart sets forth the relationship between Compensation Actually Paid to our PEOs, the average of Compensation Actually Paid to our Non-PEO | ||
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | Description of Relationship Between PEO and Non-PEO The following chart sets forth the relationship between Compensation Actually Paid to our PEOs, the average of Compensation Actually Paid to our Non-PEO Non-PEO | ||
| Total Shareholder Return Vs Peer Group [Text Block] | Description of Relationship Between Company TSR and Peer Group TSR The following chart compares our cumulative TSR over the three most recently completed fiscal years to that of the NASDAQ Biotechnology Index over the same period. | ||
| Tabular List [Table Text Block] | Tabular List of Most Important Financial Performance Measures In light of the impact of stock price on the Founders’ 2020 Performance Awards, stock price was the sole financial performance measure that the Company considers to have linked Compensation Actually Paid to our PEOs for 2022 to Company performance. The following table presents the financial performance measures that the Company considers to have been the most important in linking Compensation Actually Paid to our Non-PEO Revenue Adjusted EBITDA Gross Margin | ||
| Total Shareholder Return Amount | $ 39.25 | 156.16 | 201.22 |
| Peer Group Total Shareholder Return Amount | 113.65 | 126.45 | 126.42 |
| Net Income (Loss) | $ (654,600,000) | $ (384,800,000) | $ (246,300,000) |
| Company Selected Measure Amount | 449,500,000 | 373,700,000 | 286,700,000 |
| PEO Name | Helmy Eltoukhy | ||
| Measure [Axis]: 1 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Revenue | ||
| Non-GAAP Measure Description [Text Block] | We determined revenue to be the most important financial performance measure used to link Company performance to Compensation Actually Paid to our Non-PEO | ||
| Measure [Axis]: 2 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Adjusted EBITDA | ||
| Measure [Axis]: 3 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Gross Margin | ||
| Helmy Eltoukhy [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| PEO Total Compensation Amount | $ 11,632 | $ 13,665 | $ 113,870,986 |
| PEO Actually Paid Compensation Amount | $ (68,726,853) | (30,979,967) | 196,429,143 |
| PEO Name | Helmy Eltoukhy | ||
| AmirAli Talasaz [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| PEO Total Compensation Amount | $ 11,175 | 13,271 | 0 |
| PEO Actually Paid Compensation Amount | $ (68,727,310) | (30,980,361) | 0 |
| PEO Name | AmirAli Talasaz | ||
| PEO [Member] | Helmy Eltoukhy [Member] | Exclusion of Stock Awards and Option Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ 0 | 0 | (113,595,323) |
| PEO [Member] | Helmy Eltoukhy [Member] | Inclusion of Equity Values [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (68,738,485) | (30,993,632) | 196,153,480 |
| PEO [Member] | Helmy Eltoukhy [Member] | YearEnd Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 186,645,071 |
| PEO [Member] | Helmy Eltoukhy [Member] | Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (68,738,485) | (33,636,991) | 5,021,606 |
| PEO [Member] | Helmy Eltoukhy [Member] | VestingDate Fair Value of Equity Awards Granted During Year that Vested During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Helmy Eltoukhy [Member] | Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 2,643,359 | 4,486,803 |
| PEO [Member] | Helmy Eltoukhy [Member] | Fair Value at Last Day of Prior Year of Equity Awards Forfeited During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | AmirAli Talasaz [Member] | Exclusion of Stock Awards and Option Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | (14,375,350) | |
| PEO [Member] | AmirAli Talasaz [Member] | Inclusion of Equity Values [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (68,738,485) | (30,993,632) | |
| PEO [Member] | AmirAli Talasaz [Member] | YearEnd Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | |
| PEO [Member] | AmirAli Talasaz [Member] | Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (68,738,485) | (33,636,991) | |
| PEO [Member] | AmirAli Talasaz [Member] | VestingDate Fair Value of Equity Awards Granted During Year that Vested During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | |
| PEO [Member] | AmirAli Talasaz [Member] | Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 2,643,359 | |
| PEO [Member] | AmirAli Talasaz [Member] | Fair Value at Last Day of Prior Year of Equity Awards Forfeited During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | |
| Non-PEO NEO [Member] | Exclusion of Stock Awards and Option Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (3,261,391) | (3,651,612) | (29,326,181) |
| Non-PEO NEO [Member] | Inclusion of Equity Values [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (96,121) | 2,558,968 | 51,240,862 |
| Non-PEO NEO [Member] | YearEnd Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 1,995,203 | 2,728,176 | 48,075,762 |
| Non-PEO NEO [Member] | Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (1,584,218) | (197,657) | 1,860,798 |
| Non-PEO NEO [Member] | VestingDate Fair Value of Equity Awards Granted During Year that Vested During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (507,106) | 28,449 | 1,304,302 |
| Non-PEO NEO [Member] | Fair Value at Last Day of Prior Year of Equity Awards Forfeited During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ 0 | $ 0 | $ 0 |
