Revenue	6 Months Ended
Jun. 28, 2019
Revenue From Contract With Customer [Abstract]
Revenue	2. Revenue The Company recognizes revenue when control of promised goods or services is transferred to customers. The transfer of control generally occurs upon shipment when title and risk of loss pass to the customer. The vast majority of the Company’s revenue is generated from the sale of distinct products. Revenue is measured as the amount of consideration the Company expects to receive in exchange for such products, which is generally at contractually stated prices. Sales taxes and value added taxes collected concurrently with revenue generating activities are excluded from revenue. Performance Obligations Substantially all of the Company’s revenue is recognized at a point in time, upon shipment, rather than over time. At the request of its customers, the Company may perform professional services, generally for the maintenance and repair of products previously sold to those customers and for engineering services. Professional services are typically short in duration, mostly less than one month, and aggregate to less than 3% of the Company’s consolidated revenue. Revenue is typically recognized at a point in time when control transfers to the customer upon completion of professional services. These services generally involve a single distinct performance obligation. The consideration expected to be received in exchange for such services is normally the contractually stated amount. The Company occasionally sells separately priced non-standard/extended warranty services or preventative maintenance plans with the sale of products. The transfer of control over the service plans is over time. The Company recognizes the related revenue ratably over the terms of the service plans. The transaction price of a contract is allocated to each performance obligation based on its relative standalone selling price. Standalone selling prices are generally determined based on the prices charged to customers or using the expected cost plus a margin. Shipping & Handling Costs The Company accounts for shipping and handling activities that occur after the transfer of control over the related goods as fulfillment activities rather than performance obligations. The shipping and handling fees charged to customers are recognized as revenue and the related costs are recorded in cost of revenue at the time of transfer of control. Warranties The Company generally provides warranties for its products. The standard warranty period is typically 12 months to 24 months for the Photonics and Precision Motion segments and 12 months to 36 months for the Vision segment. The standard warranty period for product sales is accounted for under the provisions of ASC 450, “Contingencies,” as the Company has the ability to ascertain the likelihood of the liability and can reasonably estimate the amount of the liability. A provision for the estimated cost related to warranty is recorded to cost of revenue at the time revenue is recognized. The Company’s estimate of costs to service the warranty obligations is based on historical experience and expectations of future conditions. To the extent that the Company’s experience in warranty claims or costs associated with servicing those claims differ from the original estimates, revisions to the estimated warranty liability are recorded at that time, with an offsetting adjustment to cost of revenue. Practical Expedients and Exemptions The Company expenses incremental direct costs of obtaining a contract when incurred if the expected amortization period is one year or less. These costs are recorded within selling, general and administrative expenses in the consolidated statement of operations. The Company does not adjust the promised amount of consideration for the effects of a financing component because the transfer of a promised good to a customer and the customer’s payment for that good are typically one year or less. The Company does not disclose the value of the remaining performance obligation for contracts with an original expected length of one year or less. Contract Liabilities Contract liabilities consist of deferred revenue and advance payments from customers, including amounts that are refundable. These contract liabilities are classified as either current or long-term liabilities in the consolidated balance sheet based on the timing of when the Company expects to recognize revenue. As of June 28, 2019 and December 31, 2018, contract liabilities were $2.9 million and $4.7 million, respectively, and are included in accrued expenses and other current liabilities and other liabilities in the accompanying consolidated balance sheets. The decrease in the contract liability balance during the six months ended June 28, 2019 is primarily due to $3.2 million of revenue recognized during the period that was included in the contract liability balance at December 31, 2018, partially offset by cash payments received in advance of satisfying performance obligations. Disaggregated Revenue See Note 17 for the Company’s disaggregation of revenue by segment, geography and end market.

Revenue

6 Months Ended

Jun. 28, 2019

Revenue From Contract With Customer [Abstract]

2. Revenue

The Company recognizes revenue when control of promised goods or services is transferred to customers. The transfer of control generally occurs upon shipment when title and risk of loss pass to the customer. The vast majority of the Company’s revenue is generated from the sale of distinct products. Revenue is measured as the amount of consideration the Company expects to receive in exchange for such products, which is generally at contractually stated prices. Sales taxes and value added taxes collected concurrently with revenue generating activities are excluded from revenue.

Performance Obligations

Substantially all of the Company’s revenue is recognized at a point in time, upon shipment, rather than over time.

At the request of its customers, the Company may perform professional services, generally for the maintenance and repair of products previously sold to those customers and for engineering services. Professional services are typically short in duration, mostly less than one month, and aggregate to less than 3% of the Company’s consolidated revenue. Revenue is typically recognized at a point in time when control transfers to the customer upon completion of professional services. These services generally involve a single distinct performance obligation. The consideration expected to be received in exchange for such services is normally the contractually stated amount.

The Company occasionally sells separately priced non-standard/extended warranty services or preventative maintenance plans with the sale of products. The transfer of control over the service plans is over time. The Company recognizes the related revenue ratably over the terms of the service plans. The transaction price of a contract is allocated to each performance obligation based on its relative standalone selling price. Standalone selling prices are generally determined based on the prices charged to customers or using the expected cost plus a margin.

Shipping & Handling Costs

The Company accounts for shipping and handling activities that occur after the transfer of control over the related goods as fulfillment activities rather than performance obligations. The shipping and handling fees charged to customers are recognized as revenue and the related costs are recorded in cost of revenue at the time of transfer of control.

Warranties

The Company generally provides warranties for its products. The standard warranty period is typically 12 months to 24 months for the Photonics and Precision Motion segments and 12 months to 36 months for the Vision segment. The standard warranty period for product sales is accounted for under the provisions of ASC 450, “Contingencies,” as the Company has the ability to ascertain the likelihood of the liability and can reasonably estimate the amount of the liability. A provision for the estimated cost related to warranty is recorded to cost of revenue at the time revenue is recognized. The Company’s estimate of costs to service the warranty obligations is based on historical experience and expectations of future conditions. To the extent that the Company’s experience in warranty claims or costs associated with servicing those claims differ from the original estimates, revisions to the estimated warranty liability are recorded at that time, with an offsetting adjustment to cost of revenue.

Practical Expedients and Exemptions

The Company expenses incremental direct costs of obtaining a contract when incurred if the expected amortization period is one year or less. These costs are recorded within selling, general and administrative expenses in the consolidated statement of operations.

The Company does not adjust the promised amount of consideration for the effects of a financing component because the transfer of a promised good to a customer and the customer’s payment for that good are typically one year or less. The Company does not disclose the value of the remaining performance obligation for contracts with an original expected length of one year or less.

Contract Liabilities

Contract liabilities consist of deferred revenue and advance payments from customers, including amounts that are refundable. These contract liabilities are classified as either current or long-term liabilities in the consolidated balance sheet based on the timing of when the Company expects to recognize revenue. As of June 28, 2019 and December 31, 2018, contract liabilities were $2.9 million and $4.7 million, respectively, and are included in accrued expenses and other current liabilities and other liabilities in the accompanying consolidated balance sheets. The decrease in the contract liability balance during the six months ended June 28, 2019 is primarily due to $3.2 million of revenue recognized during the period that was included in the contract liability balance at December 31, 2018, partially offset by cash payments received in advance of satisfying performance obligations.

Disaggregated Revenue

See Note 17 for the Company’s disaggregation of revenue by segment, geography and end market.