v3.8.0.1
Fair Value Measurements (Details) - USD ($)
$ in Thousands
May 05, 2018
Feb. 03, 2018
Assets    
Short-term Investments $ 712,053 $ 952,790
Fair Value    
Assets    
Total assets 1,105,029 1,221,261
Fair Value | Other non-current assets | Severance pay fund    
Assets    
Other non-current assets 868 896
Fair Value | Money market funds    
Assets    
Cash equivalents 93,108 18,503
Fair Value | Time deposits    
Assets    
Cash equivalents 9,385 65,117
Fair Value | Time deposits | Short-term investments    
Assets    
Short-term Investments 100,000 150,000
Fair Value | U.S. government and agency debt    
Assets    
Cash equivalents 248,901 51,589
Fair Value | U.S. government and agency debt | Short-term investments    
Assets    
Short-term Investments 193,703 247,741
Fair Value | Foreign government and agency debt | Short-term investments    
Assets    
Short-term Investments 1,796 6,987
Fair Value | Municipal debt securities    
Assets    
Cash equivalents 5,290 5,290
Fair Value | Municipal debt securities | Short-term investments    
Assets    
Short-term Investments 1,314 2,728
Fair Value | Corporate debt securities    
Assets    
Cash equivalents 35,424 127,076
Fair Value | Corporate debt securities | Short-term investments    
Assets    
Short-term Investments 386,482 503,079
Fair Value | Asset backed securities | Short-term investments    
Assets    
Short-term Investments 28,758 42,255
Fair Value | Level 1    
Assets    
Total assets 535,712 317,833
Fair Value | Level 1 | Other non-current assets | Severance pay fund    
Assets    
Other non-current assets 0 0
Fair Value | Level 1 | Money market funds    
Assets    
Cash equivalents 93,108 18,503
Fair Value | Level 1 | Time deposits    
Assets    
Cash equivalents 0 0
Fair Value | Level 1 | Time deposits | Short-term investments    
Assets    
Short-term Investments 0 0
Fair Value | Level 1 | U.S. government and agency debt    
Assets    
Cash equivalents 248,901 51,589
Fair Value | Level 1 | U.S. government and agency debt | Short-term investments    
Assets    
Short-term Investments 193,703 247,741
Fair Value | Level 1 | Foreign government and agency debt | Short-term investments    
Assets    
Short-term Investments 0 0
Fair Value | Level 1 | Municipal debt securities    
Assets    
Cash equivalents 0 0
Fair Value | Level 1 | Municipal debt securities | Short-term investments    
Assets    
Short-term Investments 0 0
Fair Value | Level 1 | Corporate debt securities    
Assets    
Cash equivalents 0 0
Fair Value | Level 1 | Corporate debt securities | Short-term investments    
Assets    
Short-term Investments 0 0
Fair Value | Level 1 | Asset backed securities | Short-term investments    
Assets    
Short-term Investments 0 0
Fair Value | Level 2    
Assets    
Total assets 569,317 903,428
Fair Value | Level 2 | Other non-current assets | Severance pay fund    
Assets    
Other non-current assets 868 896
Fair Value | Level 2 | Money market funds    
Assets    
Cash equivalents 0 0
Fair Value | Level 2 | Time deposits    
Assets    
Cash equivalents 9,385 65,117
Fair Value | Level 2 | Time deposits | Short-term investments    
Assets    
Short-term Investments 100,000 150,000
Fair Value | Level 2 | U.S. government and agency debt    
Assets    
Cash equivalents 0 0
Fair Value | Level 2 | U.S. government and agency debt | Short-term investments    
Assets    
Short-term Investments 0 0
Fair Value | Level 2 | Foreign government and agency debt | Short-term investments    
Assets    
Short-term Investments 1,796 6,987
Fair Value | Level 2 | Municipal debt securities    
Assets    
Cash equivalents 5,290 5,290
Fair Value | Level 2 | Municipal debt securities | Short-term investments    
Assets    
Short-term Investments 1,314 2,728
Fair Value | Level 2 | Corporate debt securities    
Assets    
Cash equivalents 35,424 127,076
Fair Value | Level 2 | Corporate debt securities | Short-term investments    
Assets    
Short-term Investments 386,482 503,079
Fair Value | Level 2 | Asset backed securities | Short-term investments    
Assets    
Short-term Investments 28,758 42,255
Fair Value | Level 3    
Assets    
Total assets 0 0
Fair Value | Level 3 | Other non-current assets | Severance pay fund    
Assets    
Other non-current assets 0 0
Fair Value | Level 3 | Money market funds    
Assets    
Cash equivalents 0 0
Fair Value | Level 3 | Time deposits    
Assets    
Cash equivalents 0 0
Fair Value | Level 3 | Time deposits | Short-term investments    
Assets    
Short-term Investments 0 0
Fair Value | Level 3 | U.S. government and agency debt    
Assets    
Cash equivalents 0 0
Fair Value | Level 3 | U.S. government and agency debt | Short-term investments    
Assets    
Short-term Investments 0 0
Fair Value | Level 3 | Foreign government and agency debt | Short-term investments    
Assets    
Short-term Investments 0 0
Fair Value | Level 3 | Municipal debt securities    
Assets    
Cash equivalents 0 0
Fair Value | Level 3 | Municipal debt securities | Short-term investments    
Assets    
Short-term Investments 0 0
Fair Value | Level 3 | Corporate debt securities    
Assets    
Cash equivalents 0 0
Fair Value | Level 3 | Corporate debt securities | Short-term investments    
Assets    
Short-term Investments 0 0
Fair Value | Level 3 | Asset backed securities | Short-term investments    
Assets    
Short-term Investments $ 0 $ 0