We adopted ASC 606 on January 1, 2018, which requires revenue recognized to represent the transfer of promised goods or services to customers at an amount that reflects the consideration that a company expects to receive in exchange for those goods or services.

We utilized the modified retrospective method for adoption, allowing us to not retrospectively adjust prior periods. We applied the modified retrospective method only to contracts that were not complete at January 1, 2018 and accounted for the aggregate effect of any contract modifications upon adoption. No cumulative adjustment to retained earnings was recorded.

We disaggregate revenue from contracts with customers by payor type and major service line. We determined that disaggregating revenue into these categories achieves the disclosure objective of illustrating the differences in the nature, amount, timing and uncertainty of our revenue streams. Disaggregated revenue by payor type and major service line was as follows:



	Year Ended December 31, 2019
	Reporting Segment						Total Consolidated
(in thousands)	Healthcare		Research		Other		Total Consolidated
Payor/Service Line
Remote cardiac monitoring services - Medicare	$	153,743	$	—	$	—	$	153,743
Remote cardiac monitoring services - commercial payors	218,271		—		—		218,271
Clinical trial support and related services	—		54,450		—		54,450
Technology devices, consumable and related services	—		—		12,643		12,643
Total	$	372,014	$	54,450	$	12,643	$	439,107



	Year Ended December 31, 2018
	Reporting Segment						Total Consolidated
(in thousands)	Healthcare		Research		Other		Total Consolidated
Payor/Service Line
Remote cardiac monitoring services - Medicare	$	137,600	$	—	$	—	$	137,600
Remote cardiac monitoring services - commercial payors	201,212		—		—		201,212
Clinical trial support and related services	—		50,561		—		50,561
Technology devices, consumables and related services	—		—		10,099		10,099
Total	$	338,812	$	50,561	$	10,099	$	399,472

Healthcare segment revenue is generated by remote cardiac monitoring to identify cardiac arrhythmias or heart rhythm disorders and monitoring the functionality of implantable cardiac devices. We offer cardiologists, electrophysiologists, neurologists and primary care physicians a full spectrum of solutions which provides them with a single source of remote cardiac monitoring services.

Performance obligations are determined based on the nature of the services provided. With our remote cardiac monitoring services, the patient receives the benefits of the service over time, resulting in revenue recognition over time based on the output method. We believe that this method provides an accurate depiction of the transfer of value over the term of the performance obligation because the level of effort in providing these services is consistent during the service period.

We are utilizing the portfolio approach practical expedient in ASC 606 for our patient contracts in the Healthcare segment. We account for the contracts within each portfolio as a collective group, rather than individual contracts. Based on our history with these portfolios and the similar nature and characteristics of the patients within each portfolio, we have concluded that the financial statement effects are not materially different than if accounting for revenue on a contract-by-contract basis.

For the contracted portfolio, we have historical experience of collecting substantially all of the negotiated contractual rates and determined at contract inception that these customers have the intention and ability to pay the promised consideration. As such, we are not providing an implicit price concession but, rather, have chosen to accept the risk of default, and adjustments to the transaction price are recorded as bad debt expense.

For our non-contracted portfolio, we are providing an implicit price concession because we do not have a contract with the underlying payor, the result of which requires us to estimate our transaction price based on historical cash collections utilizing the expected value method. Subsequent adjustments to the transaction price are recorded as an adjustment to Healthcare segment revenue and not as bad debt expense.

Research segment revenue is generated by providing centralized core laboratory services, including cardiac monitoring, imaging services, scientific consulting and data management services for drug and medical device trials. These amounts are due from pharmaceutical companies and contract research organizations. We bill our customers on a fee for service basis. Under a typical contract, some customers

pay us a portion of our fee upon contract execution as an upfront refundable deposit. Upfront deposits are deferred and then recognized as the services are performed. If a contract is canceled prior to service being provided, the upfront deposit is refunded.

Performance obligations are determined based on the nature of the services provided by us. Our core laboratory services are provided over time as the customer receives benefits resulting in revenue recognition over the term of the contract. Our research customer contracts have legally enforceable terms that are predominately thirty days due to termination for convenience clauses, which are held by the customer with no significant penalty. Given the short-term nature of these contracts and the structure of our billing practices, our billing practices approximate our performance if measured by an output method, where each output is an individual occurrence of each performance obligation. Accordingly, we utilize the invoice practical expedient as defined in ASC 606, resulting in recognition of revenue in the amount that we have the right to invoice.

Our Other category revenue is primarily derived from the sale of non-invasive cardiac monitors to healthcare companies, wireless blood glucose meters and test strips to wholesale distributors of diabetes supplies and diabetic patients, as well as product repairs. Performance obligations are primarily the sale of devices, related goods and repairs provided by us. These contracts transfer control to a customer at a point in time based on the transfer of title for the underlying good or service. We provide standard warranty provisions.

We determine the transaction price based on fixed consideration in our contractual agreements with our customers and allocate the transaction price to each performance obligation based on the relative stand-alone selling price. We determine the relative stand-alone selling price utilizing our observable prices for the sale of the underlying goods.

ASC 606 requires an entity to present a revenue contract as a contract asset when the entity performs its obligations under the contract by transferring goods or services to a customer before the customer pays consideration or before payment is due. ASC 606 also requires an entity to present a revenue contract as a contract liability in instances when a customer pays consideration, or an entity has a right to an amount of consideration that is unconditional (e.g. receivable), before the entity transfers a good or service to the customer.

As of December 31, 2019 and 2018, we had contract assets of $15.1 million and $2.1 million, respectively, related to cardiac monitoring services, which are included as a component of Healthcare accounts receivable on our consolidated balance sheets. We also had contract assets of $1.7 million and $0.2 million, respectively, related to our Other category revenue contracts, which are included as a component of Other accounts receivable on our consolidated balance sheets.

As of December 31, 2019 and 2018, we had contract liabilities of $1.6 million and $3.1 million, respectively, primarily related to the Research segment where customers paid upfront deposits upon contract execution for future services to be performed by us. If the contract is canceled, these upfront deposits are refundable if service was not yet provided. For the year ended December 31, 2019, the amount recognized as revenue from the contract liability balance as of December 31, 2018 was $2.0 million. Similarly, for the year ended December 31, 2018, the amount recognized as revenue from the contract liability balance as of December 31, 2017 was $3.1 million. Our contract liabilities are included as a component of accrued liabilities on our consolidated balance sheets.

Unsatisfied Performance Obligations: Because all of our performance obligations relate to contracts with a duration of less than one year, we have elected to apply the optional exemption provided in ASC 606 and, therefore, are not required to disclose the aggregate amount of the transaction price allocated to performance obligations that are unsatisfied or partially unsatisfied at the end of the reporting period.

Contract Costs: All incremental customer contract acquisition costs are expensed as they are incurred as the amortization period of the asset that we otherwise would have recognized is one year or less in duration.

Significant Financing Component: We do not adjust the promised amount of consideration for the effects of a significant financing component as we expect, at contract inception, that the period between when we transfer a promised good or service to a customer and when the customer pays for that good or service will be one year or less.

Sales Tax Exclusion from the Transaction Price: We exclude from the measurement of the transaction price all taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction and collected by us from the customer.

Shipping and Handling Activities: For our other category revenue, we account for shipping and handling activities we perform after a customer obtains control of the good as activities to fulfill the promise to transfer the good.