Description of Business and Summary of Significant Accounting Policies (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2018 USD ($) customer	Sep. 30, 2017 customer	Sep. 30, 2018 USD ($) customer	Sep. 30, 2017 customer	Mar. 31, 2018 USD ($) customer	Apr. 01, 2018 USD ($)
Revenue Recognition
Prepaid expenses and other current assets	$ 1,033,000		$ 1,033,000		$ 1,165,000
Total assets	59,354,000		59,354,000		62,886,000
Deferred revenue	3,928,000		3,928,000		4,900,000
Total liabilities	21,725,000		21,725,000		23,365,000
Accumulated deficit	(106,648,000)		(106,648,000)		(103,519,000)
Total liabilities and stockholders' equity	59,354,000		59,354,000		$ 62,886,000
Contract Fulfillment Costs
Capitalized contract fulfillment costs	235,000		$ 235,000
Practical Expedients and Exemptions
Practical expedients not disclosing performance obligation			true
Practical expedients incremental cost			true
Prepaid Expenses and Other Current Assets
Cash designated as collateral on performance bonds	$ 130,000		$ 130,000
Percentage of cash value of the bonds as collateral			100.00%
Goodwill and Long-Lived Assets
Adjustment for impairment			$ 0
Impairment of long-lived and intangible assets			$ 0
Total revenues | Customer | One individual customer
Concentration of Credit Risk
Number of customers | customer	1	1	1	1
Percentage of concentration risk	12.00%	21.00%	15.00%	23.00%
Total revenues | Customer | No individual customer
Concentration of Credit Risk
Number of customers | customer			0	0
Total accounts receivable | Customer | One individual customer
Concentration of Credit Risk
Number of customers | customer					1
Percentage of concentration risk					13.00%
Total accounts receivable | Customer | No individual customer
Concentration of Credit Risk
Number of customers | customer			0		0
Percentage of concentration risk			10.00%
Minimum
Warranty
Warranty period			1 year
Minimum | Property and equipment
Property and Equipment, net
Useful life			3 years
Minimum | Total revenues | Customer | No individual customer
Concentration of Credit Risk
Percentage of concentration risk			10.00%	10.00%
Minimum | Total accounts receivable | Customer | No individual customer
Concentration of Credit Risk
Percentage of concentration risk					10.00%
Maximum
Warranty
Warranty period			3 years
Maximum | Property and equipment
Property and Equipment, net
Useful life			8 years
ASU 2014-09
Revenue Recognition
Prepaid expenses and other current assets						$ 1,469,000
Total assets						63,190,000
Deferred revenue						5,412,000
Total liabilities						23,877,000
Accumulated deficit						(103,727,000)
Total liabilities and stockholders' equity						$ 63,190,000
Cumulative-effect Adjustments | ASU 2014-09
Revenue Recognition
Prepaid expenses and other current assets					$ 304,000
Total assets					304,000
Deferred revenue					512,000
Total liabilities					512,000
Accumulated deficit					208,000
Total liabilities and stockholders' equity					$ 304,000