Equity (Narrative) (Details)		1 Months Ended	12 Months Ended
	Dec. 28, 2017 USD ($) shares	Jul. 31, 2016 shares	Sep. 30, 2018 USD ($) plan $ / shares shares	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2015 shares	Mar. 05, 2014 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity incentive compensation plans maintained by the company | plan			3
Intrinsic value of shares exercised | $			$ 15,000	$ 900,000	$ 87,000
Granted (in shares)			0	0
Award vesting rights			100.00%
Stock-based compensation expense | $			$ (3,648,000)	$ (3,602,000)	(2,162,000)
Common stock, shares authorized (in shares)			50,000,000	50,000,000
Preferred stock authorized (in shares)			5,882,000
Par value of preferred stock (in usd per share) | $ / shares			$ 0.0001
Common stock, shares issued (in shares)			34,487,000	33,938,000
Common stock, shares outstanding (in shares)			27,577,000	27,028,000
Preferred stock outstanding (in shares)			0	0
Preferred stock issued (in shares)			0	0
Cash matching contribution | $			$ 500,000	$ 500,000	$ 400,000
Weighted average antidilutive options, unvested restricted stock units and awards, warrants and ESPP shares excluded from the computation (in shares)			949,000	398,000	508,000
Amount of common stock issued under ESPP (in shares)			(2,775,016)
Purchases under the employee stock purchase plan (in shares)			740,558
Discontinued Operations
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense | $			$ 0	$ 0	$ (77,000)
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock purchase plan (ESPP), employee purchase price percentage			85.00%
Employee stock purchase plan (ESPP), annual employee contribution limit percentage			10.00%
Annual contribution to ESPP, limitation | $			$ 25,000
Number of shares on which options may be granted in ESPP (in shares)		3,515,574					3,250,000
Increase in number of shares to be granted under ESPP (in shares)		265,573.75
Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, average minimum vesting period (in years)			4 years
Stock options, average maximum vesting period (in years)			5 years
Stock options, contractual life (in years)			10 years
Unrecognized compensation expense | $			$ 100,000
Unrecognized compensation expense, period for recognition (in years)			2 years 4 days
Stock-based compensation expense | $			$ (32,000)	$ (45,000)	(38,000)
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unamortized stock-based compensation expense | $			$ 45,000
Remaining unamortized stock-based compensation expense, period for recognition (in years)			2 years 18 days
Unvested restricted stock units (in shares)			8,154	8,154
Granted (in usd per share) | $ / shares			$ 0.00
Granted (in shares)			0
Vested (in shares)			0
Restricted Stock Awards | Minimum | Equity incentive plans 2012 and 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)			3 years
Restricted Stock Awards | Maximum | Equity incentive plans 2012 and 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)			4 years
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unamortized stock-based compensation expense | $			$ 5,000,000
Remaining unamortized stock-based compensation expense, period for recognition (in years)			2 years 10 months 10 days
Unvested restricted stock units (in shares)			1,011,621	778,084
Outstanding non-vested RSUs aggregate intrinsic value | $			$ 4,800,000
Outstanding non-vested RSUs weighted average remaining contractual term (in years)			1 year 7 months 28 days
Intrinsic value of RSUs vested | $			$ 2,300,000	$ 3,400,000	$ 1,600,000
Granted (in usd per share) | $ / shares			$ 5.80	$ 8.20	$ 5.53
Granted (in shares)			648,043
Vested (in shares)			(374,969)
Restricted Stock Units | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	40,000
Grant date fair value | $	$ 300,000
Restricted Stock Units | Senior Vice President of Engineering
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	14,000
Grant date fair value | $	$ 100,000
Restricted Stock Units | Vice President of Sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	10,000
Grant date fair value | $	$ 100,000
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unamortized stock-based compensation expense, period for recognition (in years)			1 year 4 months 2 days
Unvested restricted stock units (in shares)			397,777	328,708
Intrinsic value of RSUs vested | $			$ 1,400,000	$ 0	$ 0
Granted (in usd per share) | $ / shares			$ 7.62	$ 8.34
Granted (in shares)	108,500		240,164		0
Grant date fair value | $	$ 900,000
Award vesting rights			200.00%
Unamortized stock based compensation | $			$ 1,500,000
Outstanding non-vested PSUs aggregate intrinsic value | $			$ 1,900,000
Weighted average remaining contractual term, PSU			1 year 4 months 2 days
Vested (in shares)			(166,058)
PSUs vested over target percentage			67,664
Performance Stock Units | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	40,000
Grant date fair value | $	$ 300,000
Performance Stock Units | Senior Vice President of Engineering
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	14,000
Grant date fair value | $	$ 100,000
Performance Stock Units | Vice President of Sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	10,000
Grant date fair value | $	$ 100,000
Performance Stock Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights	0.00%
Performance Stock Units | Minimum | Two Thousand Twelve Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)			1 year
Performance Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights	200.00%
Performance Stock Units | Maximum | Two Thousand Twelve Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)			3 years
Performance Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unamortized stock-based compensation expense, period for recognition (in years)			1 year
Unvested restricted stock units (in shares)			33,333	33,333
Granted (in usd per share) | $ / shares			$ 0.00
Granted (in shares)			0
Unamortized stock based compensation | $			$ 300,000
Vested (in shares)			0
RSU Vesting - December 28, 2018 | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights			25.00%
RSU Vesting - December 28, 2019 | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights			25.00%
RSU Vesting - December 28, 2020 | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights			25.00%
RSU Vesting - December 28, 2021 | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights			25.00%
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares outstanding (in shares)			27,577,000	27,028,000	26,244,000	25,676,000
Issuance of common stock - ESPP (in shares)			171,000	133,000	193,000