Quarterly Financial Information (Unaudited) (as restated), Condensed Consolidated Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						6 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017
Statement of Operations [Abstract]
Revenues, net	$ 7,729	$ 7,388	$ 6,738	$ 7,456	$ 8,445	$ 7,269	$ 14,126	$ 15,714	$ 21,856	$ 23,169	$ 29,855	$ 31,763
Cost of revenues	3,099	3,549	3,345	3,276	3,173	2,733	6,893	5,906	9,992	9,182	12,735	12,998
Gross profit	4,630	3,839	3,393	4,180	5,272	4,536	7,233	9,808	11,864	13,987	17,120	18,765
Operating expenses:
Engineering and product development	224	269	338	411	423	475	607	898	831	1,309	1,065	1,711
Selling and marketing	2,487	2,378	2,871	2,492	2,846	2,975	5,249	5,821	7,737	8,312	10,624	11,249
General and administrative	2,289	2,411	1,884	1,789	1,840	1,711	4,295	3,551	6,583	5,340	8,786	7,604
Total operating expenses	5,000	5,058	5,093	4,692	5,109	5,161	10,151	10,270	15,151	14,961	20,475	20,564
Income (loss) from operations	(370)	(1,219)	(1,700)	(512)	163	(625)	(2,918)	(462)	(3,287)	(974)	(3,355)	(1,799)
Other (expense) income, net:
Interest expense, net	(239)	(328)	(363)	(781)	(1,197)	(870)	(691)	(2,067)	(930)	(2,848)	(1,142)	(3,196)
Change in fair value of warrant liability	(1,053)	(263)	40	421	657	(671)	(222)	(14)	(1,275)	407	0	595
Change in fair value of embedded conversion feature			0	1,993	2,903	(1,738)	0	1,165	0	3,158	0	3,158
Income (loss) on extinguishment of debentures				(20,160)	0	0		0		(20,160)	0	(20,160)
Other income (expense), net	0	(18)	21	0	6	0	1	6	0	6	200	17
Total other (expense) income, net	(1,292)	(609)	(302)	(18,527)	2,369	(3,279)	(912)	(910)	(2,205)	(19,437)	(942)	(19,586)
Income (loss) before income taxes	(1,662)	(1,828)	(2,002)	(19,039)	2,532	(3,904)	(3,830)	(1,372)	(5,492)	(20,411)	(4,297)	(21,385)
Income tax benefit (expense)	80	(40)	(40)	(38)	(73)	(70)	(80)	(143)	0	(181)	264	(129)
Net income (loss)	(1,582)	(1,868)	(2,042)	(19,077)	2,459	(3,974)	(3,910)	(1,515)	(5,492)	(20,592)	(4,033)	(21,514)
Income (loss) attributable to common shares	(1,404)	(1,099)	(504)	(11,492)	$ 2,459	$ (3,974)	(1,728)	$ (1,515)	(3,542)	(16,650)	(2,909)	(8,851)
Loss attributable to Preferred Series C shares	$ (178)	$ (769)	$ (1,537)	$ (7,585)			$ (2,182)		$ (1,950)	$ (3,942)	$ (1,124)	$ (12,663)
Loss per common share
Basic (in dollars per share)	$ (0.05)	$ (0.08)	$ (0.12)	$ (4.64)	$ 0.90	$ (1.83)	$ (0.19)	$ (0.67)	$ (0.22)	$ (7.15)	$ (0.15)	$ (3.26)
Diluted (in dollars per share)	$ (0.05)	$ (0.08)	$ (0.12)	$ (4.64)	$ 0.01	$ (1.83)	$ (0.19)	$ (0.67)	$ (0.22)	$ (7.15)	$ (0.15)	$ (3.26)
Shares used in computing earnings (loss) per common share
Basic (in shares)	29,912,827	13,734,384	4,371,369	2,477,743	2,730,131	2,176,731	9,078,741	2,252,301	16,099,752	2,328,274	19,589,031	2,713,782
Diluted (in shares)	29,812,827	13,734,384	4,371,369	2,477,743	12,301,279	2,176,731	9,078,741	2,252,301	16,099,752	2,328,274	19,589,031	2,713,782
Loss per Preferred Series C share - basic and diluted (in dollars per share)	$ (17.73)	$ (29.77)	$ (42.69)	$ (1,723.84)			$ (70.63)		$ (81.70)	$ (2,658.44)	$ (55.20)	$ (1,212.47)
Shares used in computing loss per basic and diluted Preferred Series C share (in shares)	10,049	25,847	36,002	4,400			30,897		23,872	1,483	20,368	10,444
Previously Reported [Member]
Statement of Operations [Abstract]
Revenues, net	$ 7,892	$ 7,533	$ 6,466	$ 7,285	$ 8,471	$ 7,097	$ 13,999	$ 15,568	$ 21,892	$ 22,852		$ 31,449
Cost of revenues	3,049	3,499	3,295	3,276	3,173	2,733	6,793	5,906	9,842	9,182		13,498
Gross profit	4,843	4,034	3,171	4,009	5,298	4,364	7,206	9,662	12,050	13,670		17,951
Operating expenses:
Engineering and product development	224	269	338	411	423	475	607	898	831	1,309
Selling and marketing	2,487	2,378	2,871	2,492	2,846	2,975	5,249	5,821	7,737	8,312
General and administrative	2,184	2,333	1,803	1,678	1,720	1,601	4,136	3,321	6,319	4,999		7,401
Total operating expenses	4,895	4,980	5,012	4,581	4,989	5,051	9,992	10,040	14,887	14,620
Income (loss) from operations	(52)	(946)	(1,841)	(572)	309	(687)	(2,786)	(378)	(2,837)	(950)		(2,410)
Other (expense) income, net:
Interest expense, net	(239)	(328)	(363)	(1,343)	(1,575)	(1,346)	(691)	(2,921)	(930)	(4,264)
Change in fair value of warrant liability	(79)	(23)	0	81	128	(132)	(22)	(4)	(101)	77
Change in fair value of embedded conversion feature						0
Income (loss) on extinguishment of debentures				(11,799)	0	0		0		(11,799)
Other income (expense), net	0	(18)	21	0	6	0	1	6	0	6
Total other (expense) income, net	(318)	(369)	(342)	(13,061)	(1,441)	(1,478)	(712)	(2,919)	(1,031)	(15,980)		(16,292)
Income (loss) before income taxes	(370)	(1,315)	(2,183)	(13,633)	(1,132)	(2,165)	(3,498)	(3,297)	(3,868)	(16,930)		(18,702)
Income tax benefit (expense)	80	(40)	(40)	(38)	(73)	(70)	(80)	(143)	0	(181)
Net income (loss)	(290)	(1,355)	(2,223)	(13,671)	(1,205)	(2,235)	(3,578)	(3,440)	(3,868)	(17,111)		(18,831)
Income (loss) attributable to common shares	(257)	(797)	(547)	(8,235)	$ (1,205)	$ (2,235)	(1,580)	$ (3,440)	(2,493)	(13,835)		(7,747)
Loss attributable to Preferred Series C shares	$ (33)	$ (558)	$ (1,676)	$ (5,436)			$ (1,998)		$ (1,375)	$ (3,276)		$ (11,084)
Loss per common share
Basic (in dollars per share)	$ (0.01)	$ (0.06)	$ (0.13)	$ (3.32)	$ (0.52)	$ (1.03)	$ (0.17)	$ (1.53)	$ (0.15)	$ (5.94)
Diluted (in dollars per share)	$ (0.01)	$ (0.06)	$ (0.13)	$ (3.32)	$ (0.52)	$ (1.03)	$ (0.17)	$ (1.53)	$ (0.15)	$ (5.94)
Shares used in computing earnings (loss) per common share
Basic (in shares)	29,912,827	13,734,384	4,371,369	2,477,743	2,327,041	2,176,731	9,078,741	2,252,301	16,099,752	2,328,274
Diluted (in shares)	29,912,827	13,734,384	4,371,369	2,477,743	2,327,041	2,176,731	9,078,741	2,252,301	16,099,752	2,328,274
Loss per Preferred Series C share - basic and diluted (in dollars per share)	$ (3.23)	$ (21.60)	$ (46.54)	$ (1,235.43)			$ (64.69)		$ (57.58)	$ (2,208.96)		$ (1,061.25)
Shares used in computing loss per basic and diluted Preferred Series C share (in shares)	10,049	25,847	36,002	4,400			30,897		23,872	1,483		10,444
Sales and Use Tax [Member]
Statement of Operations [Abstract]
Revenues, net	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0		$ 0
Cost of revenues							0		0			0
Gross profit	0	0	0	0	0	0	0	0	0	0
Operating expenses:
Engineering and product development							0		0
Selling and marketing							0		0
General and administrative	128	99	104	135	147	135	203	282	331	417		304
Total operating expenses	128	99	104	135	147	135	203	282	331	417
Income (loss) from operations	(128)	(99)	(104)	(135)	(147)	(135)	(203)	(282)	(331)	(417)		(304)
Other (expense) income, net:
Interest expense, net							0		0
Change in fair value of warrant liability							0		0
Other income (expense), net							0		0
Total other (expense) income, net	0	0	0	0	0	0	0	0	0	0		0
Income (loss) before income taxes	(128)	(99)	(104)	(135)	(147)	(135)	(203)	(282)	(331)	(417)		(304)
Net income (loss)	(128)	(99)	(104)	(135)	(147)	(135)	(203)	(282)	(331)	(417)		(304)
Income (loss) attributable to common shares												0
Loss attributable to Preferred Series C shares												$ 0
Shares used in computing earnings (loss) per common share
Loss per Preferred Series C share - basic and diluted (in dollars per share)												$ 0
Shares used in computing loss per basic and diluted Preferred Series C share (in shares)												0
Warrants [Member]
Statement of Operations [Abstract]
Revenues, net	0	0	0	0	0	0	0	0	0	0		$ 0
Cost of revenues							0		0			0
Gross profit	0	0	0	0	0	0	0	0	0	0
Operating expenses:
Engineering and product development							0		0
Selling and marketing							0		0
General and administrative							0		0	0		0
Total operating expenses	0	0	0	0	0	0	0	0	0	0
Income (loss) from operations		0	0		0	0	0	0	0	0
Other (expense) income, net:
Interest expense, net							0		0
Change in fair value of warrant liability	(974)	(240)	40	340	529	(539)	(200)	(10)	(1,174)	330
Other income (expense), net					0	0	0	0	0	0
Total other (expense) income, net	(974)	(240)	40	340	529	(539)	(200)	(10)	(1,174)	330		493
Income (loss) before income taxes	(974)	(240)	40	340	529	(539)	(200)	(10)	(1,174)	330		493
Net income (loss)	(974)	(240)	40	340	529	(539)	(200)	(10)	(1,174)	330		493
Income (loss) attributable to common shares												0
Loss attributable to Preferred Series C shares												$ 0
Shares used in computing earnings (loss) per common share
Loss per Preferred Series C share - basic and diluted (in dollars per share)												$ 0
Shares used in computing loss per basic and diluted Preferred Series C share (in shares)												0
Debentures [Member]
Statement of Operations [Abstract]
Revenues, net				0	0	0		0		0		$ 0
Cost of revenues												0
Gross profit				0	0	0		0		0
Operating expenses:
General and administrative												0
Total operating expenses				0	0	0		0		0
Income (loss) from operations					0	0		0		0
Other (expense) income, net:
Interest expense, net				562	378	476		854		1,416
Change in fair value of embedded conversion feature				1,993	2,903	(1,738)		1,165		3,158
Income (loss) on extinguishment of debentures				(8,361)						(8,361)
Other income (expense), net										0
Total other (expense) income, net				(5,806)	3,281	(1,262)		2,019		(3,787)		(3,787)
Income (loss) before income taxes				(5,806)	3,281	(1,262)		2,019		(3,787)		(3,787)
Net income (loss)				(5,806)	3,281	(1,262)		2,019		(3,787)		(3,787)
Income (loss) attributable to common shares												0
Loss attributable to Preferred Series C shares												$ 0
Shares used in computing earnings (loss) per common share
Loss per Preferred Series C share - basic and diluted (in dollars per share)												$ 0
Shares used in computing loss per basic and diluted Preferred Series C share (in shares)												0
Intangible Impairment [Member]
Statement of Operations [Abstract]
Revenues, net	0	0	0	0	0	0	0	0	0	0		$ 0
Cost of revenues	50	50	50				100		150			(500)
Gross profit	(50)	(50)	(50)	0	0	0	(100)	0	(150)	0		500
Operating expenses:
Engineering and product development							0		0
Selling and marketing							0		0
General and administrative							0		0			0
Total operating expenses	0	0	0	0	0	0	0	0	0	0
Income (loss) from operations	(50)	(50)	(50)		0	0	(100)	0	(150)	0		500
Other (expense) income, net:
Interest expense, net							0		0
Change in fair value of warrant liability							0		0
Other income (expense), net							0		0
Total other (expense) income, net	0	0	0	0	0	0	0	0	0	0		0
Income (loss) before income taxes	(50)	(50)	(50)	0	0	0	(100)	0	(150)	0		500
Net income (loss)	(50)	(50)	(50)	0	0	0	(100)	0	(150)	0		500
Income (loss) attributable to common shares												0
Loss attributable to Preferred Series C shares												$ 0
Shares used in computing earnings (loss) per common share
Loss per Preferred Series C share - basic and diluted (in dollars per share)												$ 0
Shares used in computing loss per basic and diluted Preferred Series C share (in shares)												0
Deferred Revenue [Member]
Statement of Operations [Abstract]
Revenues, net	(140)	(124)	295	195	1	197	171	198	31	393		$ 415
Cost of revenues							0		0			0
Gross profit	(140)	(124)	295	195	1	197	171	198	31	393		415
Operating expenses:
Engineering and product development							0		0
Selling and marketing							0		0
General and administrative					0		0		0			0
Total operating expenses	0	0	0	0	0	0	0	0	0	0
Income (loss) from operations	(140)	(124)	295	195	1	197	171	198	31	393		415
Other (expense) income, net:
Interest expense, net							0		0
Change in fair value of warrant liability							0		0
Other income (expense), net							0		0
Total other (expense) income, net	0	0	0	0	0	0	0	0	0	0		0
Income (loss) before income taxes	(140)	(124)	295	195	1	197	171	198	31	393		415
Net income (loss)	(140)	(124)	295	195	1	197	171	198	31	393		415
Other Adjustments [Member]
Statement of Operations [Abstract]
Revenues, net	(23)	(21)	(23)	(24)	(27)	(25)	(44)	(52)	(67)	(76)		(101)
Cost of revenues							0		0			0
Gross profit	23	(21)	(23)	(24)	(27)	(25)	(44)	(52)	(67)	(76)		(101)
Operating expenses:
Engineering and product development							0		0
Selling and marketing							0		0
General and administrative	(23)	(21)	(23)	(24)	(27)	(25)	(44)	(52)	(67)	(76)		(101)
Total operating expenses	(23)	(21)	(23)	(24)	(27)	(25)	(44)	(52)	(67)	(76)
Income (loss) from operations	0	0	0		0	0	0	0	0	0		0
Other (expense) income, net:
Interest expense, net							0		0
Change in fair value of warrant liability							0		0
Other income (expense), net							0		0
Total other (expense) income, net	0	0	0	0	0	0	0	0	$ 0	0		0
Income (loss) before income taxes	0	0	0	0	0	0	0	0		0
Net income (loss)	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0		$ 0		$ 0