Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Comprehensive Deficit [Member]
BALANCE at Dec. 31, 2019	$ 48,684	$ 38	$ 274,041	$ (225,395)
BALANCE, Shares at Dec. 31, 2019		38,475,000
Non-cash compensation recognized on stock options and ESPP	48		48
Restricted stock grants, net of cancellations	2,204	$ 1	2,203
Restricted stock grants, net of cancellations, shares		1,000,000
Cancellation of shares for payment of withholding tax	(1,122)		(1,122)
Cancellation of shares for payment of withholding tax, shares		(242,000)
Employee stock purchase plan	19		19
Employee stock purchase plan, shares		6,000
Exercise of common stock warrants	4,196	$ 2	4,194
Exercise of common stock warrants, shares		2,047,000
Exercise of stock options	18		18
Exercise of stock options, shares		9,000
Net income (loss)	3,585			3,585
BALANCE at Sep. 30, 2020	57,632	$ 41	279,401	(221,810)
BALANCE, Shares at Sep. 30, 2020		41,295,000
BALANCE at Jun. 30, 2020	56,898	$ 41	278,828	(221,971)
BALANCE, Shares at Jun. 30, 2020		41,356,000
Non-cash compensation recognized on stock options and ESPP	19		19
Restricted stock grants, net of cancellations	792		792
Cancellation of shares for payment of withholding tax	(254)		(254)
Cancellation of shares for payment of withholding tax, shares		(66,000)
Employee stock purchase plan	13		13
Employee stock purchase plan, shares		4,000
Exercise of stock options	3		3
Exercise of stock options, shares		1,000
Net income (loss)	161			161
BALANCE at Sep. 30, 2020	57,632	$ 41	279,401	(221,810)
BALANCE, Shares at Sep. 30, 2020		41,295,000
BALANCE at Dec. 31, 2020	$ 58,716	$ 41	279,905	(221,230)
BALANCE, Shares at Dec. 31, 2020	41,232,804	41,233,000
Non-cash compensation recognized on stock options and ESPP	$ 61		61
Restricted stock grants, net of cancellations	3,561	$ 1	3,560
Restricted stock grants, net of cancellations, shares		1,222,000
Cancellation of shares for payment of withholding tax	(1,736)		(1,736)
Cancellation of shares for payment of withholding tax, shares		(298,000)
Employee stock purchase plan	37		37
Employee stock purchase plan, shares		10,000
Common shares issued in stock offering, net of offering costs	59,711	$ 10	59,701
Common shares issued in stock offering, net offering costs, shares		9,521,000
Common shares issued in connection with Avast Family Safety Mobile Software acquisition, net	8,381	$ 1	8,380
Common shares issued in connection with Avast Family Safety Mobile acquisition, net, shares		1,460,000
Exercise of common stock warrants	2,066	$ 2	2,064
Exercise of common stock warrants, shares		1,408,000
Exercise of stock options	58		58
Exercise of stock options, shares		18,000
Net income (loss)	(27,035)			(27,035)
BALANCE at Sep. 30, 2021	$ 103,820	$ 55	352,030	(248,265)
BALANCE, Shares at Sep. 30, 2021	54,573,823	54,574,000
BALANCE at Jun. 30, 2021	$ 119,473	$ 54	349,077	(229,658)
BALANCE, Shares at Jun. 30, 2021		53,576,000
Non-cash compensation recognized on stock options and ESPP	22		22
Restricted stock grants, net of cancellations	1,305		1,305
Restricted stock grants, net of cancellations, shares		152,000
Cancellation of shares for payment of withholding tax	(427)		(427)
Cancellation of shares for payment of withholding tax, shares		(86,000)
Employee stock purchase plan	22		22
Employee stock purchase plan, shares		5,000
Exercise of common stock warrants	2,025	$ 1	2,024
Exercise of common stock warrants, shares		924,000
Exercise of stock options	7		7
Exercise of stock options, shares		3,000
Net income (loss)	(18,607)			(18,607)
BALANCE at Sep. 30, 2021	$ 103,820	$ 55	$ 352,030	$ (248,265)
BALANCE, Shares at Sep. 30, 2021	54,573,823	54,574,000