Fair Value of Financial Instruments - Schedule of Assets Measured at Fair Value (Detail) - USD ($) $ in Thousands	Jul. 30, 2016	Jan. 30, 2016
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total cash equivalents	$ 18,316	$ 46,796
Total	198,272	199,651
Money market funds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total cash equivalents	5,421	70
Commercial paper [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total cash equivalents	12,895	46,726
Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total cash equivalents	5,421	70
Total	35,245	29,910
Level 1 [Member] | Money market funds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total cash equivalents	5,421	70
Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total cash equivalents	12,895	46,726
Total	163,027	169,741
Level 2 [Member] | Commercial paper [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total cash equivalents	12,895	46,726
Short-term investments [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	170,854	130,801
Short-term investments [Member] | Commercial paper [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	16,584	15,488
Short-term investments [Member] | Government agency obligations [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	154,270	115,313
Short-term investments [Member] | Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	29,824	22,011
Short-term investments [Member] | Level 1 [Member] | Government agency obligations [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	29,824	22,011
Short-term investments [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	141,030	108,790
Short-term investments [Member] | Level 2 [Member] | Commercial paper [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	16,584	15,488
Short-term investments [Member] | Level 2 [Member] | Government agency obligations [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	124,446	93,302
Long-term investments [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	9,102	22,054
Long-term investments [Member] | Government agency obligations [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	9,102	22,054
Long-term investments [Member] | Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments		7,829
Long-term investments [Member] | Level 1 [Member] | Government agency obligations [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments		7,829
Long-term investments [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	9,102	14,225
Long-term investments [Member] | Level 2 [Member] | Government agency obligations [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total investments	$ 9,102	$ 14,225