Basis of Presentation of Unaudited Interim Condensed Consolidated Financial Statements and Significant Accounting Policies - ASC 606 Income Statement (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018		Mar. 31, 2019	Mar. 31, 2018
Revenue:
Total Revenue	$ 65,764	$ 54,548	[1]	$ 128,077	$ 99,503	[1]
Cost of sales:
Amortization of intangibles	725	770	[1]	1,465	1,377	[1]
Total cost of sales	35,435	27,714	[1]	67,965	50,710	[1]
Gross profit	30,329	26,834	[1]	60,112	48,793	[1]
Operating expenses	29,544	26,016	[1]	53,769	49,974	[1]
Operating income (loss)	785	818	[1]	6,343	(1,181)	[1]
Net (loss) income	$ 1,342	$ (126)	[1]	$ 6,024	$ (4,613)	[1]
Diluted (loss) income (USD per share)	$ 0.05	$ 0.00	[1]	$ 0.21	$ (0.17)	[1]
Product
Revenue:
Revenue	$ 52,097	$ 47,588	[1]	$ 102,909	$ 86,042	[1]
Cost of sales:
Cost of sales excluding amortization	28,496	23,080	[1]	54,309	42,290	[1]
Services and Solutions
Revenue:
Revenue	13,667	6,960	[1]	25,168	13,461	[1]
Cost of sales:
Cost of sales excluding amortization	$ 6,214	3,864	[1]	$ 12,191	7,043	[1]
As Reported
Revenue:
Total Revenue		54,791			99,988
Cost of sales:
Amortization of intangibles		770			1,377
Total cost of sales		28,137			51,397
Gross profit		26,654			48,591
Operating expenses		26,151			50,211
Operating income (loss)		503			(1,620)
Net (loss) income		$ (357)			$ (4,926)
Diluted (loss) income (USD per share)		$ (0.01)			$ (0.18)
As Reported | Product
Revenue:
Revenue		$ 47,588			$ 86,042
Cost of sales:
Cost of sales excluding amortization		23,080			42,290
As Reported | Services and Solutions
Revenue:
Revenue		7,203			13,946
Cost of sales:
Cost of sales excluding amortization		4,287			7,730
ASU 2014-09
Revenue:
Total Revenue		54,548			99,503
Cost of sales:
Amortization of intangibles		770			1,377
Total cost of sales		27,714			50,710
Gross profit		26,834			48,793
Operating expenses		26,016			49,974
Operating income (loss)		818			(1,181)
Net (loss) income		$ (126)			$ (4,613)
Diluted (loss) income (USD per share)		$ 0.00			$ (0.17)
ASU 2014-09 | Product
Revenue:
Revenue		$ 47,588			$ 86,042
Cost of sales:
Cost of sales excluding amortization		23,080			42,290
ASU 2014-09 | Services and Solutions
Revenue:
Revenue		6,960			13,461
Cost of sales:
Cost of sales excluding amortization		3,864			7,043
ASU 2014-09 | Impact of Adoption
Revenue:
Total Revenue		(243)			(485)
Cost of sales:
Amortization of intangibles		0			0
Total cost of sales		(423)			(687)
Gross profit		180			202
Operating expenses		(135)			(237)
Operating income (loss)		315			439
Net (loss) income		$ 231			$ 313
Diluted (loss) income (USD per share)		$ 0.01			$ 0.01
ASU 2014-09 | Impact of Adoption | Product
Revenue:
Revenue		$ 0			$ 0
Cost of sales:
Cost of sales excluding amortization		0			0
ASU 2014-09 | Impact of Adoption | Services and Solutions
Revenue:
Revenue		(243)			(485)
Cost of sales:
Cost of sales excluding amortization		$ (423)			$ (687)

[1] Prior period information has been restated for the adoption of ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” which we adopted on October 1, 2018.