Fair Value Measurements - Financial Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jan. 28, 2018	Jan. 29, 2017
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	$ 1,960	$ 1,425
Cash equivalents | Level 1
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	0	16,945
Recurring
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Derivative financial instruments	0	326
Total financial assets	1,960	18,696
Total financial liabilities	21,668	1,242
Recurring | Level 1
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Derivative financial instruments	0	0
Total financial assets	0	16,945
Total financial liabilities	0	0
Recurring | Level 2
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Derivative financial instruments	0	326
Total financial assets	0	326
Total financial liabilities	0	0
Recurring | Level 3
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Derivative financial instruments	0	0
Total financial assets	1,960	1,425
Total financial liabilities	21,668	1,242
Recurring | Cash equivalents
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	0	16,945
Recurring | Cash equivalents | Level 1
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	0	16,945
Recurring | Cash equivalents | Level 2
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	0	0
Recurring | Cash equivalents | Level 3
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	0	0
Recurring | Convertible debt
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	1,960	1,425
Recurring | Convertible debt | Level 1
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	0	0
Recurring | Convertible debt | Level 2
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	0	0
Recurring | Convertible debt | Level 3
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	1,960	1,425
AptoVision | Recurring
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	21,000	0
AptoVision | Recurring | Level 1
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	0	0
AptoVision | Recurring | Level 2
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	0	0
AptoVision | Recurring | Level 3
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	21,000	0
Cycleo [Member] | Recurring
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	668	1,242
Cycleo [Member] | Recurring | Level 1
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	0	0
Cycleo [Member] | Recurring | Level 2
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	0	0
Cycleo [Member] | Recurring | Level 3
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	$ 668	$ 1,242