RESTATEMENT AND REVISION OF PRIOR PERIOD FINANCIAL STATEMENTS Condensed Consolidated Statements of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended					6 Months Ended	9 Months Ended	12 Months Ended	36 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2018	Mar. 31, 2019	Jun. 30, 2019	Jun. 30, 2019
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	$ 43,359	$ 38,508	$ 37,704	$ 34,486	$ 33,768	$ 68,254	$ 105,958	$ 144,466
Costs of sales	31,943	28,769	27,751	25,051	22,710	47,761	75,512	104,281
Gross profit	11,416	9,739	9,953	9,435	11,058	20,493	30,446	40,185
Operating expenses:
Selling, general and administrative	18,107	15,490	11,156	10,931	9,450	20,381	31,537	47,027
Investigation and restatement expenses	3,565	2,451	1,408	7,188	4,526	11,714	13,122	15,573
Integration and acquisition costs	0	211	24	181	922	1,103	1,127	1,338
Depreciation and amortization	1,022	1,071	1,083	1,143	1,133	2,276	3,359	4,430
Total operating expenses	22,694	19,223	13,671	19,443	16,031	35,474	49,145	68,368
Operating loss	(11,278)	(9,484)	(3,718)	(10,008)	(4,973)	(14,981)	(18,699)	(28,183)
Other income (expense):
Interest income	294	310	348	408	489	897	1,245	1,555
Interest expense	(465)	(474)	(913)	(819)	(786)	(1,605)	(2,518)	(2,992)
Total other income (expense), net	(171)	(164)	(565)	(411)	(297)	(708)	(1,273)	(1,437)
Loss before income taxes	(11,449)	(9,648)	(4,283)	(10,419)	(5,270)	(15,689)	(19,972)	(29,620)
(Provision) benefit for income taxes	(59)	(202)	(23)	(19)	(18)	(37)	(60)	(262)
Net loss	(11,508)	(9,850)	(4,306)	(10,438)	(5,288)	(15,726)	(20,032)	(29,882)	$ (48,600)
Preferred dividends	(334)	0	(334)	0	(334)	(334)	(668)	(668)
Net loss applicable to common shares	$ (11,842)	$ (9,850)	$ (4,640)	$ (10,438)	$ (5,622)	$ (16,060)	$ (20,700)	$ (30,550)
Net loss per common share
Basic (in dollars per share)	$ (0.20)	$ (0.16)	$ (0.08)	$ (0.17)	$ (0.09)	$ (0.27)	$ (0.34)	$ (0.51)
Diluted (in dollars per share)	$ (0.20)	$ (0.16)	$ (0.08)	$ (0.17)	$ (0.09)	$ (0.27)	$ (0.34)	$ (0.51)
Weighted average number of common shares outstanding
Basic (in shares)	60,096,852	60,065,978	60,065,053	60,059,936	60,053,912	60,056,924	60,059,594	60,061,243
Diluted (in shares)	60,096,852	60,065,978	60,065,053	60,059,936	60,053,912	60,056,924	60,059,594	60,061,243
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	$ 42,146	$ 38,225	$ 37,646	$ 34,406	$ 33,522	$ 67,928	$ 105,574	$ 143,799
Costs of sales	32,094	29,238	27,867	25,163	23,412	48,575	76,442	105,680
Gross profit	10,052	8,987	9,779	9,243	10,110	19,353	29,132	38,119
Operating expenses:
Selling, general and administrative	18,171	15,531	11,156	10,931	9,450	20,381	31,537	47,068
Investigation and restatement expenses	3,699	2,317	1,408	7,188	4,526	11,714	13,122	15,439
Integration and acquisition costs		211	24	181	922	1,103	1,127	1,338
Depreciation and amortization	1,022	1,071	1,083	1,143	1,133	2,276	3,359	4,430
Total operating expenses	22,892	19,130	13,671	19,443	16,031	35,474	49,145	68,275
Operating loss	(12,840)	(10,143)	(3,892)	(10,200)	(5,921)	(16,121)	(20,013)	(30,156)
Other income (expense):
Interest income	467	278	318	381	405	786	1,104	1,382
Interest expense	(465)	(474)	(913)	(819)	(786)	(1,605)	(2,518)	(2,992)
Total other income (expense), net	2	(196)	(595)	(438)	(381)	(819)	(1,414)	(1,610)
Loss before income taxes	(12,838)	(10,339)	(4,487)	(10,638)	(6,302)	(16,940)	(21,427)	(31,766)
(Provision) benefit for income taxes	(59)	(202)	(23)	(19)	(18)	(37)	(60)	(262)
Net loss	(12,897)	(10,541)	(4,510)	(10,657)	(6,320)	(16,977)	(21,487)	(32,028)
Preferred dividends	(334)	0	(334)	0	(334)	(334)	(668)	(668)
Net loss applicable to common shares	$ (13,231)	$ (10,541)	$ (4,844)	$ (10,657)	$ (6,654)	$ (17,311)	$ (22,155)	$ (32,696)
Net loss per common share
Basic (in dollars per share)	$ (0.22)	$ (0.18)	$ (0.08)	$ (0.18)	$ (0.11)	$ (0.29)	$ (0.37)	$ (0.54)
Diluted (in dollars per share)	$ (0.22)	$ (0.18)	$ (0.08)	$ (0.18)	$ (0.11)	$ (0.29)	$ (0.37)	$ (0.54)
Weighted average number of common shares outstanding
Basic (in shares)	60,096,852	60,065,978	60,065,053	60,059,936	60,053,912	60,056,924	60,059,594	60,061,243
Diluted (in shares)	60,096,852	60,065,978	60,065,053	60,059,936	60,053,912	60,056,924	60,059,594	60,061,243
Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	$ 1,213	$ 283	$ 58	$ 80	$ 246	$ 326	$ 384	$ 667
Costs of sales	(151)	(469)	(116)	(112)	(702)	(814)	(930)	(1,399)
Gross profit	1,364	752	174	192	948	1,140	1,314	2,066
Operating expenses:
Selling, general and administrative	(64)	(41)	0	0	0	0	0	(41)
Investigation and restatement expenses	(134)	134	0	0	0	0	0	134
Integration and acquisition costs		0	0	0	0	0	0	0
Depreciation and amortization	0	0	0	0	0	0	0	0
Total operating expenses	(198)	93	0	0	0	0	0	93
Operating loss	1,562	659	174	192	948	1,140	1,314	1,973
Other income (expense):
Interest income	(173)	32	30	27	84	111	141	173
Interest expense	0	0	0	0	0	0	0	0
Total other income (expense), net	(173)	32	30	27	84	111	141	173
Loss before income taxes	1,389	691	204	219	1,032	1,251	1,455	2,146
(Provision) benefit for income taxes	0	0	0	0	0	0	0	0
Net loss	1,389	691	204	219	1,032	1,251	1,455	2,146
Preferred dividends	0	0	0	0	0	0	0	0
Net loss applicable to common shares	$ 1,389	$ 691	$ 204	$ 219	$ 1,032	$ 1,251	$ 1,455	$ 2,146
Net loss per common share
Basic (in dollars per share)	$ 0.02	$ 0.02	$ 0.00	$ 0.01	$ 0.02	$ 0.02	$ 0.03	$ 0.03
Diluted (in dollars per share)	$ 0.02	$ 0.02	$ 0.00	$ 0.01	$ 0.02	$ 0.02	$ 0.03	$ 0.03
Weighted average number of common shares outstanding
Basic (in shares)	0	0	0	0	0	0	0	0
Diluted (in shares)	0	0	0	0	0	0	0	0
Service
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	$ 34,609	$ 32,989	$ 31,515	$ 29,733	$ 28,671	$ 58,404	$ 89,919	$ 122,908
Costs of sales	22,089	21,839	20,307	19,462	18,372	37,834	58,141	79,980
Service | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	33,833	33,116	31,630	29,837	28,971	58,808	90,438	123,554
Costs of sales	21,646	21,943	20,423	19,575	18,544	38,119	58,542	80,485
Service | Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	776	(127)	(115)	(104)	(300)	(404)	(519)	(646)
Costs of sales	443	(104)	(116)	(113)	(172)	(285)	(401)	(505)
Product
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	8,750	5,519	6,189	4,753	5,097	9,850	16,039	21,558
Costs of sales	9,854	6,930	7,444	5,589	4,338	9,927	17,371	24,301
Product | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	8,313	5,109	6,016	4,569	4,551	9,120	15,136	20,245
Costs of sales	10,448	7,295	7,444	5,588	4,868	10,456	17,900	25,195
Product | Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	437	410	173	184	546	730	903	1,313
Costs of sales	$ (594)	$ (365)	$ 0	$ 1	$ (530)	$ (529)	$ (529)	$ (894)