Fair Value Measurements - Financial Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Apr. 29, 2018	Jan. 28, 2018
Agency Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	$ 30,004	$ 0
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative financial instruments (asset)	64	0
Total financial assets	32,564	1,960
Total financial liabilities	21,668	21,668
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative financial instruments (asset)	0	0
Total financial assets	30,000	0
Total financial liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative financial instruments (asset)	64	0
Total financial assets	64	0
Total financial liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative financial instruments (asset)	0	0
Total financial assets	2,500	1,960
Total financial liabilities	21,668	21,668
Fair Value, Measurements, Recurring [Member] | Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	30,000	0
Fair Value, Measurements, Recurring [Member] | Agency Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	30,000	0
Fair Value, Measurements, Recurring [Member] | Agency Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Agency Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Convertible debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	2,500	1,960
Fair Value, Measurements, Recurring [Member] | Convertible debt | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Convertible debt | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring [Member] | Convertible debt | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale securities	2,500	1,960
Fair Value, Measurements, Recurring [Member] | AptoVision Technologies Inc.
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	21,000	21,000
Fair Value, Measurements, Recurring [Member] | AptoVision Technologies Inc. | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	0	0
Fair Value, Measurements, Recurring [Member] | AptoVision Technologies Inc. | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	0	0
Fair Value, Measurements, Recurring [Member] | AptoVision Technologies Inc. | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	21,000	21,000
Fair Value, Measurements, Recurring [Member] | Cycleo
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	668	668
Fair Value, Measurements, Recurring [Member] | Cycleo | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	0	0
Fair Value, Measurements, Recurring [Member] | Cycleo | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	0	0
Fair Value, Measurements, Recurring [Member] | Cycleo | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Earn-out liability	$ 668	$ 668