Stock Option Plans - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
Mar. 31, 2019	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of options exercised		$ 28,880
Compensation expensed not yet recognized		$ 17,920
ISO and NSO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option term		10 years
Vesting term		4 years
ISO and NSO \| 10% Stockholders
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise threshold as a percentage of fair value of shares		110.00%
ISO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise threshold as a percentage of fair value of shares		100.00%
NSO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise threshold as a percentage of fair value of shares		85.00%
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting term		4 years
Restricted stock vested (in shares)		0
Compensation expensed not yet recognized, period for recognition		3 years 2 months 23 days
Unrecognized compensation costs of unvested RSUs		$ 1,228
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expensed not yet recognized, period for recognition		3 years 18 days
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares allowable under the plan (in shares)	1,200,000
Percent of outstanding shares of common stock	1.00%
Common stock reserved for future issuance (in shares)	434,000	746,552
Percent of purchase of price of common stock		85.00%
Share of stock issued in ESPP (in shares)		87,567
Shares available for future issuance (in shares)		658,985
Compensation expensed not yet recognized, period for recognition		1 month 6 days
Unrecognized compensation costs related to the ESPP		$ 106
2019 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance (in shares)	2,317,000	3,633,180
Percent of outstanding shares of common stock	4.00%
2019 Equity Incentive Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares allowable under the plan (in shares)	3,000,000

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Share-Based Compensation Arrangement By Share-based Payment Award, Number Of Additional Shares Allowable Under The Plan

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.

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Purchase price of common stock expressed as a percentage of its fair value.

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