Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value Based on Three-Tier Fair Value Hierarchy (Detail) - USD ($)		Oct. 02, 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
Time deposit pledged for credit card facility	[1]	1,091,000
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		43,396,000	$ 57,915,000
Total liabilities measured and recorded at fair value		326,000	7,000
Fair Value, Measurements, Recurring [Member] | Prepaids and other current assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Time deposit pledged for credit card facility		580,000
Fair Value, Measurements, Recurring [Member] | Cost-method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		2,587,000	2,606,000
Money market funds [Member] | Fair Value, Measurements, Recurring [Member] | Cash equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		14,062,000	23,121,000
State, municipal and local government agencies bonds [Member] | Fair Value, Measurements, Recurring [Member] | Short-term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		2,503,000	13,961,000
Corporate bonds [Member] | Fair Value, Measurements, Recurring [Member] | Short-term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		23,487,000	17,886,000
Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Prepaids and other current assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		177,000	341,000
Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Accrued Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured and recorded at fair value		326,000	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		16,649,000	25,727,000
Total liabilities measured and recorded at fair value		0	0
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Prepaids and other current assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Time deposit pledged for credit card facility		0
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Cost-method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		2,587,000	2,606,000
Level 1 [Member] | Money market funds [Member] | Fair Value, Measurements, Recurring [Member] | Cash equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		14,062,000	23,121,000
Level 1 [Member] | State, municipal and local government agencies bonds [Member] | Fair Value, Measurements, Recurring [Member] | Short-term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		0	0
Level 1 [Member] | Corporate bonds [Member] | Fair Value, Measurements, Recurring [Member] | Short-term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		0	0
Level 1 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Prepaids and other current assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		0	0
Level 1 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Accrued Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
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		26,747,000	32,188,000
Total liabilities measured and recorded at fair value		326,000	7,000
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Prepaids and other current assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Time deposit pledged for credit card facility		580,000
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Cost-method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		0	0
Level 2 [Member] | Money market funds [Member] | Fair Value, Measurements, Recurring [Member] | Cash equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		0	0
Level 2 [Member] | State, municipal and local government agencies bonds [Member] | Fair Value, Measurements, Recurring [Member] | Short-term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		2,503,000	13,961,000
Level 2 [Member] | Corporate bonds [Member] | Fair Value, Measurements, Recurring [Member] | Short-term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		23,487,000	17,886,000
Level 2 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Prepaids and other current assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		177,000	341,000
Level 2 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Accrued Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured and recorded at fair value		326,000	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
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Prepaids and other current assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Time deposit pledged for credit card facility		0
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Cost-method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		0	0
Level 3 [Member] | Money market funds [Member] | Fair Value, Measurements, Recurring [Member] | Cash equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		0	0
Level 3 [Member] | State, municipal and local government agencies bonds [Member] | Fair Value, Measurements, Recurring [Member] | Short-term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		0	0
Level 3 [Member] | Corporate bonds [Member] | Fair Value, Measurements, Recurring [Member] | Short-term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		0	0
Level 3 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Prepaids and other current assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured and recorded at fair value		0	0
Level 3 [Member] | Foreign exchange forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Accrued Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured and recorded at fair value		$ 0	$ 0

[1] The Company has restricted cash of $0.5 million that serves as collateral for rent guarantees on certain operating leases in Israel. Additionally, the Company holds $0.6 million of restricted cash as collateral for its corporate card credit facility in Switzerland. These restricted funds are invested in bank deposits and cannot be withdrawn from the Company’s accounts without the prior written consent of the applicable secured party.