RESTATEMENT OF CONSOLIDATED FINANCIAL STATEMENTS - Restated Consolidated Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended												6 Months Ended		9 Months Ended		12 Months Ended			36 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2018	Mar. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2019
OPERATING ACTIVITIES:
Net loss	$ (10,541)	$ (4,510)	$ (10,657)	$ (6,320)	$ (1,696)	$ (3,223)	$ (4,194)	$ (2,171)	$ (2,938)	$ (925)	$ (232)	$ (3,370)	$ (6,365)	$ (3,602)	$ (9,588)	$ (4,527)	$ (32,028)	$ (11,284)	$ (7,465)	$ (50,800)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Non-cash stock-based compensation								409				211	984	445	1,424	678	1,750	1,794	1,214
(Gain) loss on disposal of property and equipment								(18)					(80)	(34)	(99)	(59)	672	(131)	(177)
Non-cash interest and amortization of debt discount								17				139	94	65	118	98	301	140	113
Bad debt expense								168				199	382	331	510	460	2,534	471	557
Provision for inventory reserve								221				248	1,091	480	1,361	804	3,172	1,467	877
Depreciation and amortization								1,370				1,603	3,278	3,164	5,586	4,679	8,009	7,829	5,956
Change in fair value of warrant liabilities										0	0	1,490		1,490		1,490	0	0	1,490
Deferred income taxes, net								16				15	(159)	30	(154)	46	(7)	(183)	62
Recognition of deferred gain from sale-leaseback transactions								0				0	0	0	0	0			0
Changes in operating assets and liabilities:
Accounts receivable								(3,149)				(1,003)	(5,332)	(2,418)	(9,964)	(2,316)	(8,488)	(6,234)	(2,538)
Finance receivables, net								9,168				(5)	7,332	2,119	8,202	(2,180)	(8)	2,228	(10,832)
Inventory, net								(3,900)				(2,713)	(7,615)	(3,403)	(7,777)	(2,957)	(5,242)	(3,661)	(4,463)
Prepaid expenses and other current assets								(103)				(124)	(2)	(442)	355	(454)	(395)	377	153
Accounts payable and accrued expenses																			8,874
Deferred revenue								171				(59)	570	326	351	157	(98)	351	115
Income taxes payable								(55)				(3)	(40)	3	(30)	4	254	(13)	(8)
Net cash (used in) provided by operating activities								721				(5,915)	1,909	(4,146)	7,668	(2,815)	(28,701)	12,431	(6,072)
INVESTING ACTIVITIES:
Purchase of property and equipment, including rentals								(720)				(623)	(1,734)	(1,752)	(3,138)	(2,536)	(4,346)	(3,978)	(3,787)
Proceeds from sale of property and equipment								45					157	61	252	105	116	298	348
Net cash used in investing activities								(675)				(623)	(66,758)	(1,691)	(68,067)	(2,431)	(4,230)	(68,861)	(3,439)
FINANCING ACTIVITIES:
Cash used in retirement of common stock												(31)		(31)	(156)	(31)	(81)	(552)	(31)
Proceeds from exercise of common stock warrants												6,193		6,193		6,193	0	0	6,193
Payment of debt issuance costs													(445)		(445)	(90)	(156)	(445)	(90)
Repayment of line of credit													(7,111)	(106)	(7,111)	(106)	0	(7,111)	(106)
Repayment of capital lease obligations and long-term debt								(809)				(698)	(1,043)	(1,457)	(3,751)	(2,212)	(23,254)	(5,355)	(2,982)
Net cash (used in) provided by financing activities								39,079				5,464	67,464	4,599	64,709	3,754	(23,569)	127,649	2,984
Net (decrease) increase in cash and cash equivalents								39,125				(1,074)	2,615	(1,238)	4,310	(1,492)	(56,500)	71,219	(6,527)
Cash and cash equivalents at beginning of year				$ 83,964	17,055	15,360	51,870	12,745	17,780	18,034	18,198	19,272	12,745	19,272	12,745	19,272	83,964	12,745	19,272	19,272
Cash and cash equivalents at end of year	$ 27,464				83,964	17,055	15,360	51,870	12,745	17,780	18,034	18,198	15,360	18,034	17,055	17,780	$ 27,464	83,964	12,745	27,464
As Previously Reported
OPERATING ACTIVITIES:
Net loss						1,160	(12,516)	(213)	243	136	233	(2,464)	(12,729)	(2,231)	(11,569)	(2,095)			(1,852)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Non-cash stock-based compensation								576				211	1,356	445	2,005	678			1,214
(Gain) loss on disposal of property and equipment								(18)					(83)	(31)	(112)	(59)			(177)
Non-cash interest and amortization of debt discount								15				105	86	26	100	98			113
Bad debt expense								118				97	291	450	506	577			764
Provision for inventory reserve								0				0	0	0	0	0			0
Depreciation and amortization								1,492				1,301	3,476	2,564	5,858	3,774			5,591
Change in fair value of warrant liabilities										0	0	1,490		1,490		1,490			1,490
Deferred income taxes, net								(535)				(115)	8,537	(115)	6,400	94			54
Recognition of deferred gain from sale-leaseback transactions								(43)				(215)	(93)	(430)	(143)	(646)			(560)
Changes in operating assets and liabilities:
Accounts receivable								(3,192)				(1,038)	(5,290)	(2,347)	(12,972)	(2,388)			(2,988)
Finance receivables, net								8,771				(5)	7,958	2,119	11,114	(2,113)			(12,119)
Inventory, net								(3,648)				(2,223)	(5,822)	(2,689)	(5,624)	(2,042)			(2,399)
Prepaid expenses and other current assets								(217)				(224)	(606)	(542)	(564)	(406)			(304)
Accounts payable and accrued expenses																			4,410
Deferred revenue								0				0	0	0	(185)	0			0
Income taxes payable								0				(10)	40	(12)	0	(18)			(8)
Net cash (used in) provided by operating activities								1,005				(6,265)	4,138	(5,143)	8,689	(4,295)			(6,771)
INVESTING ACTIVITIES:
Purchase of property and equipment, including rentals								(992)				(810)	(1,767)	(1,944)	(3,005)	(2,818)			(4,041)
Proceeds from sale of property and equipment								45					157	61	252	105			348
Net cash used in investing activities								(947)				(810)	(66,791)	(1,883)	(67,934)	(2,713)			(3,693)
FINANCING ACTIVITIES:
Cash used in retirement of common stock												(31)		(31)	(156)	(31)			(31)
Proceeds from exercise of common stock warrants												6,193		6,193		6,193			6,193
Payment of debt issuance costs													(445)		(445)	(90)			(90)
Repayment of line of credit													(7,111)	0	(7,111)	0			(106)
Repayment of capital lease obligations and long-term debt								(821)				(161)	(2,138)	(374)	(3,778)	(556)			(2,029)
Net cash (used in) provided by financing activities								39,067				6,001	65,294	5,788	63,607	5,516			3,937
Net (decrease) increase in cash and cash equivalents								39,125				(1,074)	2,641	(1,238)	4,362	(1,492)			(6,527)
Cash and cash equivalents at beginning of year					17,107	15,386	51,870	12,745	17,780	18,034	18,198	19,272	12,745	19,272	12,745	19,272		12,745	19,272	19,272
Cash and cash equivalents at end of year						17,107	15,386	51,870	12,745	17,780	18,034	18,198	15,386	18,034	17,107	17,780			12,745
Adjustments
OPERATING ACTIVITIES:
Net loss						(4,383)	8,322	(1,958)	(3,181)	(1,061)	(465)	(906)	6,364	(1,371)	1,981	(2,432)			(5,613)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Non-cash stock-based compensation								(167)				0	(372)	0	(581)	0			0
(Gain) loss on disposal of property and equipment								0					3	(3)	13	0			0
Non-cash interest and amortization of debt discount								2				34	8	39	18	0			0
Bad debt expense								50				102	91	(119)	4	(117)			(207)
Provision for inventory reserve								221				248	1,091	480	1,361	804			877
Depreciation and amortization								(122)				302	(198)	600	(272)	905			365
Change in fair value of warrant liabilities										0	0	0		0		0			0
Deferred income taxes, net								551				130	(8,696)	145	(6,554)	(48)			8
Recognition of deferred gain from sale-leaseback transactions								43				215	93	430	143	646			560
Changes in operating assets and liabilities:
Accounts receivable								43				35	(42)	(71)	3,008	72			450
Finance receivables, net								397				0	(626)	0	(2,912)	(67)			1,287
Inventory, net								(252)				(490)	(1,793)	(714)	(2,153)	(915)			(2,064)
Prepaid expenses and other current assets								114				100	604	100	919	(48)			457
Accounts payable and accrued expenses																			4,464
Deferred revenue								171				(59)	570	326	536	157			115
Income taxes payable								(55)				7	(80)	15	(30)	22			0
Net cash (used in) provided by operating activities								(284)				350	(2,229)	997	(1,021)	1,480			699
INVESTING ACTIVITIES:
Purchase of property and equipment, including rentals								272				187	33	192	(133)	282			254
Proceeds from sale of property and equipment								0					0	0	0	0			0
Net cash used in investing activities								272				187	33	192	(133)	282			254
FINANCING ACTIVITIES:
Cash used in retirement of common stock												0		0	0	0			0
Proceeds from exercise of common stock warrants												0		0		0			0
Payment of debt issuance costs													0		0	0			0
Repayment of line of credit													0	(106)	0	(106)			0
Repayment of capital lease obligations and long-term debt								12				(537)	1,095	(1,083)	27	(1,656)			(953)
Net cash (used in) provided by financing activities								12				(537)	2,170	(1,189)	1,102	(1,762)			(953)
Net (decrease) increase in cash and cash equivalents								0				0	(26)	0	(52)	0			0
Cash and cash equivalents at beginning of year					$ (52)	(26)	0	0	0	0	0	0	0	0	0	0		$ 0	0	$ 0
Cash and cash equivalents at end of year						$ (52)	$ (26)	$ 0	$ 0	$ 0	$ 0	$ 0	$ (26)	$ 0	$ (52)	$ 0			$ 0