Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value Based on Three-Tier Fair Value Hierarchy (Detail) - USD ($) | Jul. 03, 2015 | Dec. 31, 2014 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Liabilities, Fair Value Disclosure, Nonrecurring | $ 0 | |
Assets, Fair Value Disclosure, Nonrecurring | 0 | |
Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 59,246,000 | $ 57,915,000 |
Total liabilities measured and recorded at fair value | 81,000 | 7,000 |
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 29,530,000 | 25,727,000 |
Total liabilities measured and recorded at fair value | 0 | 0 |
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 29,716,000 | 32,188,000 |
Total liabilities measured and recorded at fair value | 81,000 | 7,000 |
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 0 | 0 |
Total liabilities measured and recorded at fair value | 0 | 0 |
Cash equivalents [Member] | Money market funds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 25,956,000 | 23,121,000 |
Cash equivalents [Member] | Level 1 [Member] | Money market funds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 25,956,000 | 23,121,000 |
Cash equivalents [Member] | Level 2 [Member] | Money market funds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 0 | 0 |
Cash equivalents [Member] | Level 3 [Member] | Money market funds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 0 | 0 |
Short-term investments [Member] | State, municipal and local government agencies bonds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 8,872,000 | 13,961,000 |
Short-term investments [Member] | Corporate bonds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 20,162,000 | 17,886,000 |
Short-term investments [Member] | Level 1 [Member] | State, municipal and local government agencies bonds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 0 | 0 |
Short-term investments [Member] | Level 1 [Member] | Corporate bonds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 0 | 0 |
Short-term investments [Member] | Level 2 [Member] | State, municipal and local government agencies bonds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 8,872,000 | 13,961,000 |
Short-term investments [Member] | Level 2 [Member] | Corporate bonds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 20,162,000 | 17,886,000 |
Short-term investments [Member] | Level 3 [Member] | State, municipal and local government agencies bonds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 0 | 0 |
Short-term investments [Member] | Level 3 [Member] | Corporate bonds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 0 | 0 |
Prepaids and other current assets [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 682,000 | 341,000 |
Prepaids and other current assets [Member] | Level 1 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 0 | 0 |
Prepaids and other current assets [Member] | Level 2 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 682,000 | 341,000 |
Prepaids and other current assets [Member] | Level 3 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 0 | 0 |
Cost-method Investments [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 3,574,000 | 2,606,000 |
Cost-method Investments [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total assets measured and recorded at fair value | 3,574,000 | 2,606,000 |
Accrued Liabilities [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total liabilities measured and recorded at fair value | 81,000 | 7,000 |
Accrued Liabilities [Member] | Level 1 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total liabilities measured and recorded at fair value | 0 | 0 |
Accrued Liabilities [Member] | Level 2 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total liabilities measured and recorded at fair value | 81,000 | 7,000 |
Accrued Liabilities [Member] | Level 3 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Total liabilities measured and recorded at fair value | $ 0 | $ 0 |