Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (unaudited) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock	Series C Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2019	$ (123,338)	$ 130,666			$ 4,419	$ (127,757)
Balance, Shares at Dec. 31, 2019		209,119,674		230,860
Issuance of Series C redeemable convertible preferred stock, net of issuance costs			$ 29,446
Issuance of Series C redeemable convertible preferred stock, net of issuance costs, Shares			78,306,611
Accretion of convertible preferred stock to redemption value	(85)				(85)
Temporary equity, Accretion of convertible preferred stock to redemption value		$ 85
Issuance of common stock warrants in conjunction with sale of Series C redeemable convertible preferred stock	740				740
Stock-based compensation	134				134
Net loss	(4,232)					(4,232)
Balance at Mar. 31, 2020	(126,781)	$ 160,197			5,208	(131,989)
Balance, Shares at Mar. 31, 2020		287,426,285		230,860
Balance at Dec. 31, 2020	74,492			$ 13	224,363	(149,884)
Balance, Shares at Dec. 31, 2020				12,932,377
Exercise of common stock options	$ 262				262
Exercise of common stock options, Shares	30,391			30,391
Stock-based compensation	$ 599				599
Net loss	(7,802)					(7,802)
Balance at Mar. 31, 2021	$ 67,551			$ 13	$ 225,224	$ (157,686)
Balance, Shares at Mar. 31, 2021				12,962,768