Stock Based Compensation - Executive grants (Details) | Jun. 08, 2020USD ($)$ / sharesshares | May 15, 2020USD ($)$ / sharesshares | May 14, 2020USD ($) | Apr. 15, 2020USD ($)$ / sharesshares | Apr. 30, 2019Option | Apr. 29, 2019Option$ / shares | Aug. 31, 2020USD ($)shares | Dec. 31, 2020USD ($)itemshares | Dec. 31, 2019USD ($)shares | Dec. 31, 2018USD ($) |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Reverse Recapitalization Exchange Rate | | | | | | | | 0.7471 | | |
Chief executive officer options to purchase shares | shares | | | | | | | | 15,000,000 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage, Quarterly | | | | | | | | 5.00% | | |
Share Based Compensation Related Shares Founder Grants | | | | | | | | $ 47,841,859 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | | | | | | | | 47,841,859 | | |
Share Based Compensation Related Shares Founder Grants | | | | | | | | $ 47,841,859 | | |
Share-based Payment Arrangement, Expense | | | | | | | | 23,757,000 | $ 1,237,000 | $ 6,680,000 |
Compensation expense recognized | | | | | | | | $ 23,757,000 | $ 1,237,000 | $ 6,680,000 |
Issuance of common stock upon early exercise of stock options with promissory note (in shares) | shares | | | | | | | | 15,000,000 | | |
Board of Directors Chairman [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage, Quarterly | | | | | | | 6.25% | | | |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | | | | | | | | $ 2,300,000 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | | | | | | | 2,757,886 | | | |
Compensation expense | | | | | | | $ 23,500,000 | | | |
Vesting percentage | | | | | | | 25.00% | | | |
Founders Options [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Employee Benefits and Share-based Compensation | | | | | | | | 800,000 | | |
Grant date fair value of option recognized as compensation expense over the requisite service period | | | | | | | | $ 93,400,000 | | |
Class A common stock | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Reverse Recapitalization Exchange Rate | | | | | | | | | 0.7471 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | | | | | | | | 24,669,278 | | |
Class B Common Stock [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Employee Benefits and Share-based Compensation | | | | | | | | | $ 11,000,000 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | | | | | | | | 8,172,581 | 700,000 | |
Old Skillz Class A Common Stock [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights | | | | | | | | 50 | | |
Vesting period | | | | | | | | 50 | | |
Old Skillz Class A Common Stock [Member] | Chief Executive Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price | $ / shares | | | | $ 1.15 | | | | | | |
Old Skillz Class B Common Stock [Member] | Chief Technology Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights | 50 | | | | | | | | | |
Vesting period | 50 | | | | | | | | | |
New Skillz Class B Common Stock [Member] | Chief Executive Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | | | | | | | | 9,960,000 | | |
New Skillz Class A common stock [Member] | Chief Revenue Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | | | | | | | | 2,040,000 | | |
General and administrative | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Payment Arrangement, Expense | | | | | | | | | $ 2,300,000 | |
Compensation expense recognized | | | | | | | | | 2,300,000 | |
Sales and marketing | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Payment Arrangement, Expense | | | | | | | | | 700,000 | |
Compensation expense recognized | | | | | | | | | 700,000 | |
Research and development | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Payment Arrangement, Expense | | | | | | | | | 400,000 | |
Compensation expense recognized | | | | | | | | | $ 400,000 | |
Executive grants | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Number of separate options to purchase shares of Class A common stock | Option | | | | | 2 | 2 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage, Quarterly | | | | | | | | 25.00% | | |
Executive grants | Promissory note | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Debt Instrument, Interest Rate During Period | | | 0.58% | | | | | | | |
Outstanding principal of promissory note | | | $ 11,400,000 | | | | | $ 3,800,000 | | |
Interest rate | | | | | | | | 2.55% | | |
Maximum term of promissory note | | | | | | | | 9 years | | |
Executive grants | Chief Executive Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | | | | | | | | $ 21,500,000 | | |
Employee Benefits and Share-based Compensation | | | $ 3,800,000 | | | | | | | |
Vesting percentage | | | | | | | | 100.00% | | |
Executive grants | Class A common stock | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Exercise price of options | $ / shares | | | | | | $ 0.43 | | | | |
Executive grants | Class A common stock | Promissory note | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Issuance of common stock upon early exercise of stock options with promissory note (in shares) | shares | | | | | | | | 8,970,517 | | |
Executive grants | Class B Common Stock [Member] | Chief Executive Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price | $ / shares | | $ 1.15 | | | | | | | | |
Executive grants | Old Skillz Class A Common Stock [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | | | 4 years | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage, Quarterly | | | | | | | | 6.25% | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights | | | | | | | | 100 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | | | | | | | | 9,921,314 | | |
Vesting period | | | | | | | | 100 | | |
Vesting percentage | | | | | | | | 25.00% | | |
Executive grants | Old Skillz Class B Common Stock [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights | | 50 | | | | | | | | |
Vesting period | | 50 | | | | | | | | |
First option | Old Skillz Class B Common Stock [Member] | Chief Technology Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | 4 years | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage, Quarterly | 6.25% | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights | 100 | | | | | | | | | |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 9,000,000 | | | | | | | | | |
Employee Benefits and Share-based Compensation | | | | | | | | $ 900,000 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | 1,520,736 | | | | | | | | | |
Vesting period | 100 | | | | | | | | | |
Vesting percentage | 25.00% | | | | | | | 100.00% | | |
First option | Executive grants | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Payment Arrangement, Expense | | | | | | | | $ 700,000 | | |
Grant date fair value of option recognized as compensation expense over the requisite service period | | | | | | | | 1,700,000 | | |
Compensation expense recognized | | | | | | | | $ 700,000 | | |
First option | Executive grants | Chief Revenue Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage, Quarterly | | | | | | | | 100.00% | | |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | | $ 3,500,000 | | | | | | | | |
Employee Benefits and Share-based Compensation | | | | | | | | $ 600,000 | | |
First option | Executive grants | Class A common stock | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Chief executive officer options to purchase shares | shares | | | | | | | | 2,990,172 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights | | | | | | | | P4Y | | |
Vesting period | | | | | | | | P4Y | | |
Vesting percentage | | | | | | | | 0.021% | | |
First option | Executive grants | Class A common stock | Vesting of then-outstanding shares upon the consummation of an IPO | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Vesting percentage | | | | | | | | 50.00% | | |
First option | Executive grants | Class A common stock | Vesting of then-outstanding shares upon the earlier of Exit Transaction or termination of service | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Vesting percentage | | | | | | | | 100.00% | | |
First option | Executive grants | Old Skillz Class B Common Stock [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | 4 years | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage, Quarterly | | 6.25% | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights | | 100 | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | | 1,852,695 | | | | | | | | |
Vesting period | | 100 | | | | | | | | |
Vesting percentage | | 25.00% | | | | | | | | |
Second option | Old Skillz Class B Common Stock [Member] | Chief Technology Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price | $ / shares | $ 1.33 | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | 919,862 | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value | $ 3,700,000 | | | | | | | | | |
Second option | Old Skillz Class B Common Stock [Member] | Minimum | Chief Technology Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value | 1,800,000,000 | | | | | | | | | |
Second option | Old Skillz Class B Common Stock [Member] | Maximum | Chief Technology Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value | $ 3,000,000,000 | | | | | | | | | |
Second option | Executive grants | Chief Revenue Officer [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value | | | | $ 2,000,000 | | | | | | |
Second option | Executive grants | Minimum | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Market condition targets | | | | | | | | $ 600,000,000 | | |
Second option | Executive grants | Class A common stock | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Chief executive officer options to purchase shares | shares | | | | | | | | 5,980,344 | | |
Number of market condition targets related to the valuation of the Company | item | | | | | | | | 8 | | |
Grant date fair value of option recognized as compensation expense over the requisite service period | | | | | | | | $ 900,000 | | |
Second option | Executive grants | Class A common stock | Maximum | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Market condition targets | | | | | | | | $ 2,700,000,000 | | |
Second option | Executive grants | Class B Common Stock [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Debt Instrument, Interest Rate During Period | | | 0.58% | | | | | | | |
Share Based Compensation Related Shares Founder Grants | | | $ 2,779,042 | | | | | | | |
Share Based Compensation Related Shares Founder Grants | | | 2,779,042 | | | | | | | |
Outstanding principal of promissory note | | | $ 3,200,000 | | | | | | | |
Second option | Executive grants | Old Skillz Class B Common Stock [Member] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | shares | | | | 926,347 | | | | | | |
Second option | Executive grants | Old Skillz Class B Common Stock [Member] | Minimum | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value | | | | $ 1,500,000,000 | | | | | | |
Second option | Executive grants | Old Skillz Class B Common Stock [Member] | Maximum | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value | | | | $ 2,700,000,000 | | | | | | |