Condensed Consolidated Statements Of Operations And Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues:
Revenues	$ 444
Cost and expenses:
Cost of revenues	909
Research and development	6,769	$ 9,063
Sales and marketing	5,541	4,146
General and administrative	4,498	5,316
Total costs and expenses	17,717	18,525
Loss from operations	(17,273)	(18,525)
Other income (expense):
Interest income (expense), net		(114)
Total other income (expense)		(114)
Net loss	(17,273)	(18,639)
Other comprehensive gain (loss):
Unrealized gain (loss) on available-for-sale securities		1
Comprehensive loss	$ (17,273)	$ (18,638)
Net loss per share:
Basic and diluted net loss per share	$ (0.58)	$ (0.71)
Weighted average shares used to compute net loss per common share - basic and diluted	29,745	26,072
Product [Member]
Revenues:
Revenues	$ 444