Share-Based Compensation - Narrative (Details)				12 Months Ended
		Oct. 05, 2016 USD ($) $ / shares mo shares	Feb. 26, 2014 $ / shares	Jan. 29, 2017 USD ($) $ / shares shares		Jan. 31, 2016 USD ($) $ / shares	Jan. 25, 2015 USD ($) $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax benefit realized from option exercise activity | $				$ 0		$ 0	$ 0
Dividend yield				0.00%		0.00%	0.00%
Number of shares authorized per the equity incentive plan | shares				14,832,355
Potential per share consideration due upon change in control				$ 40.00
Number of employees affected by modification of awards				12
Incremental cost related to modification of awards | $				$ 0
Maximum number of shares subject to purchase under warrants | shares		1,086,957
Common stock, par value		$ 0.01		$ 0.01		$ 0.01
Fair value of warrant shares | $		$ 30,000,000
Number of trading days used to determine average closing price of shares subject to warrants		10
Exercise price of warrants (per share)		$ 0.01
Percent of warrants vested upon issuance		10.00%
Number of months in milestone period of warrants | mo		30
Warrants, contractual term		7 years		7 years
Reason for issuing to warrants		The Warrant was issued by the Company to Comcast in connection with an agreement between the parties regarding the intended trial deployment by Comcast of a low-power wide-area Network ("LPWAN") in the United States, based on the Company’s LoRa wireless Radio Frequency ("RF") technology.
Number of performance tranches of warrants		5
Performance-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period				3 years
Performance condition, highest potential performance level				200.00%
Maximum number of shares which would be settled in shares | shares				378,000
Remaining value of shares which would be settled in cash | shares				378,000
Target performance metrics for performance unit awards, fiscal year 2017				190.00%
Target performance metrics for performance unit awards, fiscal year 2016				0.00%
Weighted average fair value units granted (in dollars per share)	[2]			$ 17.51	[1]	28.60	$ 24.74
Market performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value units granted (in dollars per share)				$ 0.00
Employee stock unit awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Weighted average fair value units granted (in dollars per share)				$ 22.12		20.79	$ 23.90
Minimum | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				3 years
Maximum | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Contractual term of equity share options				10 years
Subject to cash settlement | Performance-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase (decrease) in liability | $				$ 1,440,000
Subject to cash settlement | Non-employee director stock unit awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				1 year
Vested but unsettled stock units | shares				173,657
Subject to share settlement | Non-employee director stock unit awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				1 year
Chief Executive Officer | Tranche One | Market performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield							0.00%
Share-based compensation, terms of award			The award is eligible to vest during the period commencing February 26, 2014 and ending February 26, 2019 (the “Performance Period”) as follows: 30% of the restricted stock units covered by the award will vest if, during any consecutive 120 calendar day period that commences and ends during the Performance Period, the average per-share closing price of the Company’s common stock equals or exceeds $35.00 (“Tranche 1”) and the award will vest in full if, during any consecutive 120 calendar day period that commences and ends during the Performance Period, the average per-share closing price of the Company’s common stock equals or exceeds $40.00 (“Tranche 2”). The award will also vest if a majority change in control of the Company occurs during the Performance Period and, in connection with such event, the Company’s stockholders become entitled to receive per-share consideration having a value equal to or greater than $40.00.
Percentage of award that will vest upon satisfaction of performance condition			30.00%
Award performance period			120 days
Minimum closing share price used to determine market condition			$ 35.00
Weighted average fair value units granted (in dollars per share)			$ 17.26				$ 17.26
Chief Executive Officer | Tranche Two | Market performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield							0.00%
Percentage of award that will vest upon satisfaction of performance condition			100.00%
Award performance period			120 days
Minimum closing share price used to determine market condition			$ 40.00
Weighted average fair value units granted (in dollars per share)			$ 14.88				$ 14.88
Warrant shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares subject to purchase under warrants | shares				1,086,957
Exercise price of warrants (per share)				$ 27.74		$ 0
Warrants exercised | shares				0
Other long-term liabilities | Subject to cash settlement | Non-employee director stock unit awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation liability, long-term | $				$ 6,300,000

[1] Includes 189,000 of restricted stock unit awards that will be cash settled and 196,000 of awards that will be settled in shares.

[2] nits granted includes awards that will be cash settled of 115,500 in fiscal year 2017, 90,500 in fiscal year 2016, and 128,016 in fiscal year 2015.