CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment
Redeemable convertible preferred stock, beginning balance (in shares) at Dec. 31, 2017			61,279,079
Redeemable convertible preferred stock, beginning balance at Dec. 31, 2017			$ 166,486
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock in connection with the initial public offering (in shares)			(61,279,079)
Conversion of redeemable convertible preferred stock in connection with the initial public offering	$ (166,486)		$ (166,486)
Redeemable convertible preferred stock, ending balance (in shares) at Dec. 31, 2018			0
Redeemable convertible preferred stock, ending balance at Dec. 31, 2018		$ (11,799)	$ 0				$ (11,799)
Beginning balance (in shares) at Dec. 31, 2017				33,740,323
Beginning balance at Dec. 31, 2017	(31,367)			$ 3	$ 92,222	$ (123,592)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				3,567,917
Issuance of common stock upon exercise of stock options and common stock warrants	8,160			$ 1	8,159
Stock-based compensation expense	10,361				10,361
Issuance of common stock in connection with the initial public offering, net of discounts and commissions (in shares)				7,840,908
Issuance of common stock in connection with the initial public offering, net of discounts and commissions	109,381			$ 1	109,380
Costs related to the initial public offering	(6,282)				(6,282)
Conversion of redeemable convertible preferred stock warrant in connection with the initial public offering	7,160				7,160
Conversion of redeemable convertible preferred stock in connection with the initial public offering (in shares)				61,279,079
Conversion of redeemable convertible preferred stock in connection with the initial public offering	166,486			$ 6	166,480
Issuance of common stock for settlement of RSUs (in shares)				38,742
Shares withheld related to net share settlement of RSUs (in shares)				(12,648)
Shares withheld related to net share settlement of RSUs	(247)				(247)
Net loss	(19,907)					(19,907)
Ending balance at Dec. 31, 2018	243,745			$ 11	387,233	(143,499)
Ending balance (in shares) at Dec. 31, 2018				106,454,321
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock in connection with the initial public offering	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				6,429,471
Issuance of common stock upon exercise of stock options and common stock warrants	18,155				18,155
Stock-based compensation expense	18,616				18,616
Tides Foundation common stock warrant expense and other	975				975
Conversion of redeemable convertible preferred stock warrant in connection with the initial public offering	0
Issuance of common stock for settlement of RSUs (in shares)				163,943
Issuance of common stock in connection with employee stock purchase plan (in shares)				556,663
Issuance of common stock in connection with employee stock purchase plan	6,391				6,391
Net loss	(16,659)					(16,659)
Ending balance at Dec. 31, 2019	259,424			$ 11	431,370	(171,957)
Ending balance (in shares) at Dec. 31, 2019				113,604,398
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of redeemable convertible preferred stock in connection with the initial public offering	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)	9,065,976			9,115,947
Issuance of common stock upon exercise of stock options and common stock warrants	$ 31,028				31,027
Stock-based compensation expense	25,677				25,677
Tides Foundation common stock warrant expense and other	1,135				1,135
Conversion of redeemable convertible preferred stock warrant in connection with the initial public offering	0
Issuance of common stock for settlement of RSUs (in shares)				1,590,225
Issuance of common stock in connection with employee stock purchase plan (in shares)				484,652
Issuance of common stock in connection with employee stock purchase plan	4,913				4,913
Net loss	(22,867)					(22,867)
Ending balance at Dec. 31, 2020	$ 299,310			$ 12	$ 494,122	$ (194,824)
Ending balance (in shares) at Dec. 31, 2020				124,795,222