Note 2 - Revenue Recognition	9 Months Ended
Sep. 30, 2019
Notes to Financial Statements
Revenue from Contract with Customer [Text Block]	2. REVENUE RECOGNITION Revenue from Product Sales The Company generates revenue primarily from product sales, which include assembled and tested integrated circuits, as well as dies in wafer form. These product sales were 99% and 98% of the Company’s total revenue for the three months ended September 30, 2019 and 2018, respectively, and 99% and 98% of the Company’s total revenue for the nine months ended September 30, 2019 and 2018, respectively. The remaining revenue primarily includes royalty revenue from licensing arrangements and revenue from wafer testing services performed for third parties, which have not been significant in all periods presented. See Note 8 for the disaggregation of the Company’s revenue by geographic regions and by product families. The Company sells its products primarily through third-party distributors, value-added resellers, original equipment manufacturers, original design manufacturers and electronic manufacturing service providers. For the three months ended September 30, 2019 and 2018, 88% and 87%, respectively, of the Company’s product sales were made through distribution arrangements. For the nine months ended September 30, 2019 and 2018, 83% and 87%, respectively, of the Company’s product sales were made through distribution arrangements. These distribution arrangements contain enforceable rights and obligations specific to those distributors and not the end customers. Purchase orders, which are generally governed by sales agreements or the Company's standard terms of sale, set the final terms for unit price, quantity, shipping and payment agreed by both parties. The Company considers purchase orders to be the contracts with customers. The unit price as stated on the purchase orders is considered the observable, stand-alone selling price for the arrangements. The Company recognizes revenue when it satisfies a performance obligation by transferring control of the promised goods or services to its customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company excludes taxes assessed by government authorities, such as sales taxes, from revenue. Product sales consist of a single performance obligation that the Company satisfies at a point in time. The Company recognizes product revenue from distributors and direct end customers when the following events have occurred: (a) the Company has transferred physical possession of the products, (b) the Company has a present right to payment, (c) the customer has legal title to the products, and (d) the customer bears significant risks and rewards of ownership of the products. In accordance with the shipping terms specified in the contracts, these criteria are generally met when the products are shipped from the Company’s facilities (such as the “Ex Works” shipping term) or delivered to the customers’ locations (such as the “Delivered Duty Paid” shipping term). Under certain consignment agreements, revenue is not recognized when the products are shipped and delivered to be held at customers’ designated locations because the Company continues to control the products and retain ownership, and the customers do not have an unconditional obligation to pay. The Company recognizes revenue when the customers consume the products from the consigned inventory locations or, in some cases, after a 60-day period from the delivery date has passed, at which time control transfers to the customers and the Company invoices them for payment. Variable Consideration The Company accounts for price adjustment and stock rotation rights as variable consideration that reduces the transaction price, and recognizes that reduction in the same period the associated revenue is recognized. Three U.S.-based distributors have price adjustment rights when they sell the Company’s products to their end customers at a price that is lower than the distribution price invoiced by the Company. When the Company receives claims from the distributors that products have been sold to the end customers at the lower price, the Company issues the distributors credit memos for the price adjustments. The Company estimates the price adjustments using the expected value method based on an analysis of historical claims, at both the distributor and product level, as well as an assessment of any known trends of product sales mix. Other U.S. distributors and non-U.S. distributors, which make up the majority of the Company’s total sales to distributors, do not have price adjustment rights. The Company records a credit against accounts receivable for the estimated price adjustments, with a corresponding reduction to revenue. Certain distributors have limited stock rotation rights that permit the return of a small percentage of the previous six months’ purchases in accordance with the contract terms. The Company estimates the stock rotation returns using the expected value method based on an analysis of historical returns, and the current level of inventory in the distribution channel. The Company records a liability for the stock rotation reserve, with a corresponding reduction to revenue. In addition, the Company recognizes an asset for product returns which represents the right to recover products from the customers related to stock rotations, with a corresponding reduction to cost of revenue. Contract Balances The Company records a receivable when it has an unconditional right to receive consideration after the performance obligations are satisfied. As of September 30, 2019 and December 31, 2018, accounts receivable totaled $58.3 million and $55.2 million, respectively. The Company did not record any allowance for doubtful accounts as of September 30, 2019 and December 31, 2018. For certain customers located in Asia, the Company requires cash payments two weeks before the products are scheduled to be shipped to the customers. The Company records these payments received in advance of performance as customer prepayments within current accrued liabilities. As of September 30, 2019 and December 31, 2018, customer prepayments totaled $4.2 million and $2.5 million, respectively. The increase in the customer prepayment balance for the nine months ended September 30, 2019 resulted from an increase in unfulfilled customer orders for which the Company has received payments. For the nine months ended September 30, 2019, the Company recognized $2.5 million of revenue that was included in the customer prepayment balance as of December 31, 2018. Practical Expedients The Company has elected the practical expedient to expense sales commissions as incurred because the amortization period would have been one year or less. The Company’s standard payment terms generally require customers to pay 30 to 60 days after the Company satisfies the performance obligations. For those customers who are required to pay in advance, the Company satisfies the performance obligations generally within two weeks. The Company has elected not to determine whether contacts with customers contain significant financing components. The Company’s unsatisfied performance obligations primarily include products held in consignment arrangements and customer purchase orders for products that the Company has not yet shipped. Because the Company expects to fulfill these performance obligations within one year, the Company has elected not to disclose the amount of these remaining performance obligations or the timing of recognition.

Note 2 - Revenue Recognition

9 Months Ended

Sep. 30, 2019

Revenue from Contract with Customer [Text Block]

2. REVENUE RECOGNITION

Revenue from Product Sales

The Company generates revenue primarily from product sales, which include assembled and tested integrated circuits, as well as dies in wafer form. These product sales were 99% and 98% of the Company’s total revenue for the three months ended September 30, 2019 and 2018, respectively, and 99% and 98% of the Company’s total revenue for the nine months ended September 30, 2019 and 2018, respectively. The remaining revenue primarily includes royalty revenue from licensing arrangements and revenue from wafer testing services performed for third parties, which have not been significant in all periods presented. See Note 8 for the disaggregation of the Company’s revenue by geographic regions and by product families.

The Company sells its products primarily through third-party distributors, value-added resellers, original equipment manufacturers, original design manufacturers and electronic manufacturing service providers. For the three months ended September 30, 2019 and 2018, 88% and 87%, respectively, of the Company’s product sales were made through distribution arrangements. For the nine months ended September 30, 2019 and 2018, 83% and 87%, respectively, of the Company’s product sales were made through distribution arrangements. These distribution arrangements contain enforceable rights and obligations specific to those distributors and not the end customers. Purchase orders, which are generally governed by sales agreements or the Company's standard terms of sale, set the final terms for unit price, quantity, shipping and payment agreed by both parties. The Company considers purchase orders to be the contracts with customers. The unit price as stated on the purchase orders is considered the observable, stand-alone selling price for the arrangements.

The Company recognizes revenue when it satisfies a performance obligation by transferring control of the promised goods or services to its customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company excludes taxes assessed by government authorities, such as sales taxes, from revenue.

Product sales consist of a single performance obligation that the Company satisfies at a point in time. The Company recognizes product revenue from distributors and direct end customers when the following events have occurred: (a) the Company has transferred physical possession of the products, (b) the Company has a present right to payment, (c) the customer has legal title to the products, and (d) the customer bears significant risks and rewards of ownership of the products. In accordance with the shipping terms specified in the contracts, these criteria are generally met when the products are shipped from the Company’s facilities (such as the “Ex Works” shipping term) or delivered to the customers’ locations (such as the “Delivered Duty Paid” shipping term).

Under certain consignment agreements, revenue is not recognized when the products are shipped and delivered to be held at customers’ designated locations because the Company continues to control the products and retain ownership, and the customers do not have an unconditional obligation to pay. The Company recognizes revenue when the customers consume the products from the consigned inventory locations or, in some cases, after a 60-day period from the delivery date has passed, at which time control transfers to the customers and the Company invoices them for payment.

Variable Consideration

The Company accounts for price adjustment and stock rotation rights as variable consideration that reduces the transaction price, and recognizes that reduction in the same period the associated revenue is recognized. Three U.S.-based distributors have price adjustment rights when they sell the Company’s products to their end customers at a price that is lower than the distribution price invoiced by the Company. When the Company receives claims from the distributors that products have been sold to the end customers at the lower price, the Company issues the distributors credit memos for the price adjustments. The Company estimates the price adjustments using the expected value method based on an analysis of historical claims, at both the distributor and product level, as well as an assessment of any known trends of product sales mix. Other U.S. distributors and non-U.S. distributors, which make up the majority of the Company’s total sales to distributors, do not have price adjustment rights. The Company records a credit against accounts receivable for the estimated price adjustments, with a corresponding reduction to revenue.

Certain distributors have limited stock rotation rights that permit the return of a small percentage of the previous six months’ purchases in accordance with the contract terms. The Company estimates the stock rotation returns using the expected value method based on an analysis of historical returns, and the current level of inventory in the distribution channel. The Company records a liability for the stock rotation reserve, with a corresponding reduction to revenue. In addition, the Company recognizes an asset for product returns which represents the right to recover products from the customers related to stock rotations, with a corresponding reduction to cost of revenue.

Contract Balances

The Company records a receivable when it has an unconditional right to receive consideration after the performance obligations are satisfied. As of September 30, 2019 and December 31, 2018, accounts receivable totaled $58.3 million and $55.2 million, respectively. The Company did not record any allowance for doubtful accounts as of September 30, 2019 and December 31, 2018.

For certain customers located in Asia, the Company requires cash payments two weeks before the products are scheduled to be shipped to the customers. The Company records these payments received in advance of performance as customer prepayments within current accrued liabilities. As of September 30, 2019 and December 31, 2018, customer prepayments totaled $4.2 million and $2.5 million, respectively. The increase in the customer prepayment balance for the nine months ended September 30, 2019 resulted from an increase in unfulfilled customer orders for which the Company has received payments. For the nine months ended September 30, 2019, the Company recognized $2.5 million of revenue that was included in the customer prepayment balance as of December 31, 2018.

Practical Expedients

The Company has elected the practical expedient to expense sales commissions as incurred because the amortization period would have been one year or less.

The Company’s standard payment terms generally require customers to pay 30 to 60 days after the Company satisfies the performance obligations. For those customers who are required to pay in advance, the Company satisfies the performance obligations generally within two weeks. The Company has elected not to determine whether contacts with customers contain significant financing components.

The Company’s unsatisfied performance obligations primarily include products held in consignment arrangements and customer purchase orders for products that the Company has not yet shipped. Because the Company expects to fulfill these performance obligations within one year, the Company has elected not to disclose the amount of these remaining performance obligations or the timing of recognition.