CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Balances at beginning of period at Dec. 31, 2021	$ 46,258,000	$ 15,000	$ 351,394,000	$ (304,107,000)	$ (1,044,000)
Balances at beginning of period (in shares) at Dec. 31, 2021		15,532,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from vesting of restricted stock units,shares (Note 7)		557,000
Tax withholding related to vesting of restricted stock units	(404,000)		(404,000)
Issuance of common stock under employee stock purchase plan	22,000	$ 1,000	21,000
Issuance of common stock under employee stock purchase plan (in shares)		13,000
Stock-based compensation expense	2,691,000		2,691,000
Net loss	(13,109,000)			(13,109,000)
Foreign currency translation adjustments	83,000				83,000
Balances at end of period at Sep. 30, 2022	35,541,000	$ 16,000	353,702,000	(317,216,000)	(961,000)
Balances at end of period (in shares) at Sep. 30, 2022		16,102,000
Balances at beginning of period at Dec. 31, 2021	46,258,000	$ 15,000	351,394,000	(304,107,000)	(1,044,000)
Balances at beginning of period (in shares) at Dec. 31, 2021		15,532,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(18,227,000)
Balances at end of period at Dec. 31, 2022	32,714,000	$ 17,000	355,996,000	(322,334,000)	(965,000)
Balances at end of period (in shares) at Dec. 31, 2022		17,226,000
Balances at beginning of period at Jun. 30, 2022	40,551,000	$ 16,000	353,018,000	(311,480,000)	(1,003,000)
Balances at beginning of period (in shares) at Jun. 30, 2022		15,887,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from vesting of restricted stock units,shares (Note 7)		215,000
Tax withholding related to vesting of restricted stock units	(300,000)		(300,000)
Stock-based compensation expense	984,000		984,000
Net loss	(5,736,000)			(5,736,000)
Foreign currency translation adjustments	42,000				42,000
Balances at end of period at Sep. 30, 2022	35,541,000	$ 16,000	353,702,000	(317,216,000)	(961,000)
Balances at end of period (in shares) at Sep. 30, 2022		16,102,000
Balances at beginning of period at Dec. 31, 2022	32,714,000	$ 17,000	355,996,000	(322,334,000)	(965,000)
Balances at beginning of period (in shares) at Dec. 31, 2022		17,226,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from vesting of restricted stock units,shares (Note 7)		796,000
Issuance of common stock from vesting of restricted stock units (Note 7)		$ 1,000
Tax withholding related to vesting of restricted stock units	(231,000)		(231,000)
Issuance of common stock under employee stock purchase plan	6,000		6,000
Issuance of common stock under employee stock purchase plan (in shares)		13,000
Stock-based compensation expense	2,681,000		2,681,000
Net loss	(16,654,000)			(16,654,000)
Foreign currency translation adjustments	1,000				(1,000)
Balances at end of period at Sep. 30, 2023	18,518,000	$ 18,000	358,452,000	(338,988,000)	(964,000)
Balances at end of period (in shares) at Sep. 30, 2023		18,035,000
Balances at beginning of period at Jun. 30, 2023	23,254,000	$ 18,000	358,259,000	(334,034,000)	(989,000)
Balances at beginning of period (in shares) at Jun. 30, 2023		17,723,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from vesting of restricted stock units,shares (Note 7)		312,000
Issuance of common stock from vesting of restricted stock units (Note 7)		$ 0
Tax withholding related to vesting of restricted stock units	(126,000)		(126,000)
Stock-based compensation expense	319,000		319,000
Net loss	(4,954,000)			(4,954,000)
Foreign currency translation adjustments	25,000				25,000
Balances at end of period at Sep. 30, 2023	$ 18,518,000	$ 18,000	$ 358,452,000	$ (338,988,000)	$ (964,000)
Balances at end of period (in shares) at Sep. 30, 2023		18,035,000