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Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions |  |  |  |  | 3 Months Ended | 12 Months Ended
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Mar. 05, 2019 $ / shares shares | Apr. 27, 2018 shares | Oct. 05, 2016 shares | Feb. 26, 2014 | Apr. 29, 2018 USD ($) employee shares | Jan. 26, 2020 USD ($) $ / shares shares | Jan. 27, 2019 USD ($) $ / shares shares | Jan. 28, 2018 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Weighted average fair value on grant date (in dollars per share) | $ / shares |  |  |  |  |  |  | $ 14.53 | $ 10.70
Number of shares authorized per the equity incentive plan |  |  |  |  |  | 17,031,653 |  |
Aggregate unrecognized compensation for stock options | $ |  |  |  |  |  | $ 1.9 |  |
Number of employees affected by modification of awards | employee |  |  |  |  | 8 |  |  |
Number of shares affected (in shares) |  |  |  |  | 159,000 |  |  |
Additional compensation cost | $ |  |  |  |  | $ 2.8 |  |  |
Maximum number of shares subject to purchase under warrants |  |  | 1,086,957 |  |  |  |  |
Number of shares underlying the Warrant that vested |  | 586,956 |  |  |  |  |  |
Warrant vesting costs | $ |  |  |  |  |  |  | $ 21.5 |
Warrant vesting costs due to acceleration | $ |  |  |  |  |  |  | $ 15.9 |
Number of securities called by warrants (in shares) |  |  |  |  |  |  | 869,565 |
Stock options |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Period over which aggregate unrecognized compensation will be recognized |  |  |  |  |  | 2 years 2 months 12 days |  |
Market Performance Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Awards vested (in shares) |  |  |  |  |  | 79,245 |  |
Weighted average fair value units granted (in dollars per share) | $ / shares |  |  |  |  |  | $ 59.49 |  |
Stock units granted (in shares) |  |  |  |  |  | 266,000 | 200,442 | 215,857
Total number of unvested shares (in shares) |  |  |  |  |  | 257,000 | 203,000 |
Performance-based RSUs |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Aggregate unrecognized compensation | $ |  |  |  |  |  | $ 8.4 |  |
Period over which aggregate unrecognized compensation will be recognized |  |  |  |  |  | 1 year 7 months 6 days |  |
Performance Based Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  |  | 3 years |
Percentage of award that will vest upon satisfaction of performance condition |  |  |  |  |  |  | 180.80% |
Total number of unvested shares (in shares) |  |  |  |  |  | 0 |  |
Awards settled value | $ |  |  |  |  |  | $ 9.3 |  |
Employee stock unit awards |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  | 4 years |  |
Awards vested (in shares) |  |  |  |  |  | 892,000 |  |
Aggregate unrecognized compensation | $ |  |  |  |  |  | $ 71.8 |  |
Period over which aggregate unrecognized compensation will be recognized |  |  |  |  |  | 2 years 4 months 24 days |  |
Weighted average fair value units granted (in dollars per share) | $ / shares |  |  |  |  |  | $ 47.88 |  |
Stock units granted (in shares) |  |  |  |  |  | 921,000 |  |
Total number of unvested shares (in shares) |  |  |  |  |  | 2,102,000 | 2,204,000 |
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 Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Awards vested (in shares) |  |  |  |  |  | 187,116 |  |
Subject to share settlement | Performance Based Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Awards vested (in shares) |  |  |  |  |  | 187,116 |  |
Tranche One | Market Performance Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  | 1 year |  |
Performance period |  |  |  |  |  | 1 year |  |
Weighted average fair value units granted (in dollars per share) | $ / shares |  |  |  |  |  | $ 55.82 |  |
Tranche Two | Market Performance Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  | 2 years |  |
Performance period |  |  |  |  |  | 2 years |  |
Weighted average fair value units granted (in dollars per share) | $ / shares |  |  |  |  |  | $ 59.36 |  |
Tranche Three | Market Performance Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  | 3 years |  |
Performance period |  |  |  |  |  | 3 years |  |
Weighted average fair value units granted (in dollars per share) | $ / shares |  |  |  |  |  | $ 61.45 |  |
Tranche Four | Market Performance Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  | 4 years |  |
Performance period |  |  |  |  |  | 4 years |  |
Weighted average fair value units granted (in dollars per share) | $ / shares |  |  |  |  |  | $ 62.98 |  |
Vesting January 26, 2020 | Market Performance Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Awards scheduled to vest (in shares) |  |  |  |  |  | 214,100 |  |
Chief Executive Officer | Market Performance Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Aggregate unrecognized compensation | $ |  |  |  |  |  | $ 4.8 |  |
Period over which aggregate unrecognized compensation will be recognized | 1 year 1 month 6 days |  |  |  |  |  |  |
Potential per share consideration due upon change in control | $ / shares |  |  |  |  |  | $ 71.00 |  |
Stock units granted (in shares) | 320,000 |  |  |  |  |  |  |
Chief Executive Officer | Tranche One | Market Performance Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Percentage of award that will vest upon satisfaction of performance condition | 30.00% |  |  |  |  |  |  |
Award performance period | 30 days |  |  |  |  |  |  |
Minimum closing share price used to determine market condition (usd per share) | $ / shares | $ 71.00 |  |  |  |  |  |  |
Weighted average fair value units granted (in dollars per share) | $ / shares | $ 44.32 |  |  |  |  |  |  |
Chief Executive Officer | Tranche One | Market performance RSUs |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
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. |  |  |  |
Chief Executive Officer | Tranche Two | Market Performance Restricted Stock Units |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Award performance period | 30 days |  |  |  |  |  |  |
Minimum closing share price used to determine market condition (usd per share) | $ / shares | $ 95.00 |  |  |  |  |  |  |
Weighted average fair value units granted (in dollars per share) | $ / shares | $ 33.19 |  |  |  |  |  |  |
Chief Executive Officer | Tranche Two | Market performance RSUs |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Percentage of award that will vest upon satisfaction of performance condition |  |  |  | 100.00% |  |  |  |
Non-employee director stock unit awards | Restricted Stock Units (RSUs) |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  | 1 year |  |
Awards vested (in shares) |  |  |  |  |  | 26,000 |  |
Stock units vested but unsettled |  |  |  |  |  | 190,873 |  |
Share-based compensation liability, long-term | $ |  |  |  |  |  | $ 10.5 |  |
Weighted average fair value units granted (in dollars per share) | $ / shares |  |  |  |  |  | $ 50.55 |  |
Stock units granted (in shares) |  |  |  |  |  | 26,000 |  |
Total number of unvested shares (in shares) |  |  |  |  |  | 26,000 | 26,000 |
Non-employee director stock unit awards | Subject to cash settlement | Restricted Stock Units (RSUs) |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Awards vested (in shares) |  |  |  |  |  | 14,000 |  |
Stock units granted (in shares) |  |  |  |  |  | 14,000 |  |
Total number of unvested shares (in shares) |  |  |  |  |  | 14,000 | 14,000 |
Non-employee director stock unit awards | Subject to share settlement | Restricted Stock Units (RSUs) |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Awards vested (in shares) |  |  |  |  |  | 12,000 |  |
Stock units granted (in shares) |  |  |  |  |  | 12,000 |  |
Total number of unvested shares (in shares) |  |  |  |  |  | 12,000 | 12,000 |

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- Definition Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(2)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
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- Definition Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition An excess of the fair value of the modified award over the fair value of the award immediately before the modification. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(2)(iii) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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