Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended
	Apr. 04, 2015 segment	Mar. 29, 2014
Summary Of Significant Accounting Policies [Line Items]
Number of Sources of Product Revenue	4masi_NumberofSourcesofProductRevenue
Interest Paid, Net	$ 413,000us-gaap_InterestPaidNet	$ 15,000us-gaap_InterestPaidNet
Depreciation	2,700,000us-gaap_Depreciation	2,200,000us-gaap_Depreciation
Impairment of goodwill, intangible assets and other long-lived assets	0
Number of days royalty revenue is adjusted subsequent to quarter end	60 days
Warranty period, minimum, long-term sales agreement	3 years
Warranty period, maximum, long-term sales agreement	6 years
Options to purchase of shares of common stock	3.2	2.8
Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block]	Impairment of Goodwill and Intangible Assets Goodwill is recorded as the difference, if any, between the aggregate consideration paid for an acquisition and the fair value of the acquired net tangible and intangible assets. Goodwill is not amortized, but instead is tested annually for impairment, or more frequently when events or changes in circumstances indicate that goodwill might be impaired. In assessing goodwill impairment for each of its reporting units, the Company has the option to first assess the qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. The Company’s qualitative assessment of the recoverability of goodwill considers various macroeconomic, industry-specific and Company-specific factors, including: (i) severe adverse industry or economic trends; (ii) significant Company-specific actions; (iii) current, historical or projected deterioration of the Company’s financial performance; or (iv) a sustained decrease in the Company’s market capitalization below its net book value. If, after assessing the totality of events or circumstances, the Company determines it is unlikely that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary. However, if the Company concludes otherwise, then the Company is required to perform the first step of the two-step impairment test by comparing the fair value of the reporting unit, determined using future projected discounted operating cash flows, with its carrying amount, including goodwill. If the fair value of the reporting unit exceeds its carrying amount, goodwill is not considered impaired; otherwise, goodwill is considered impaired and the loss is measured by performing step two. Under step two, the impairment loss is measured by comparing the implied fair value of the reporting unit goodwill with the carrying amount of goodwill. The Company also has the option to bypass the qualitative assessment and proceed directly to performing the first step of the two-step goodwill impairment test. The Company may resume performing the qualitative assessment in any subsequent period. The annual impairment test is performed during the fourth fiscal quarter. The Company reviews long-lived assets and identifiable intangibles for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted operating cash flow expected to be generated by the asset. If such asset is considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount exceeds the fair value of the asset. Long-lived assets to be disposed of are reported at the lower of carrying amount or fair value less costs to sell. No impairment of goodwill, intangible assets or other long-lived assets was recorded during the three months ended April 4, 2015 or March 29, 2014.
Income Taxes Paid	6,673,000us-gaap_IncomeTaxesPaid	1,838,000us-gaap_IncomeTaxesPaid
Capital Lease Obligations Incurred	36,000us-gaap_CapitalLeaseObligationsIncurred	0us-gaap_CapitalLeaseObligationsIncurred
Capital Expenditures Incurred but Not yet Paid	4,346,000	302,000
Stock repurchased, unsettled at period end	6,079	0
Patents
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Assets, Cost Incurred to Renew or Extend	$ 100,000	$ 200,000
Weighted average number of years until the next renewal	1 year
Trademarks
Summary Of Significant Accounting Policies [Line Items]
Weighted average number of years until the next renewal	5 years
Minimum
Summary Of Significant Accounting Policies [Line Items]
Warranty period for defects in material and workmanship	6 months
Maximum
Summary Of Significant Accounting Policies [Line Items]
Warranty period for defects in material and workmanship	15 months
Building [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	39 years
Leasehold improvements \| Minimum
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Leasehold improvements \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	6 years
Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Computer equipment
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Demonstration units
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Tooling
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Furniture and Office Equipment [Member] \| Minimum
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Furniture and Office Equipment [Member] \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	6 years
Demonstration Units [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	3 years