Revenue is recognized upon transfer of control of promised products or services to customers in an amount that reflects the consideration the Company expects to receive in exchange for those products or services. The Company enters into contracts that can include various combinations of products and services, which when capable of being distinct, are accounted for as separate performance obligations. Revenue recognition is evaluated based on the following five steps: (i) identification of the contract with the customer; (ii) identification of the performance obligations in the contract; (iii) determination of the transaction price; (iv) allocation of the transaction price to the performance obligations in the contract; and (v) recognition of revenue when or as a performance obligation is satisfied.

 

For multiple-element arrangements, revenue is allocated to each performance obligation based on its relative standalone selling price. Standalone selling prices are determined based on observable prices at which the Company separately sells its products or services. If a standalone selling price is not directly observable, the Company estimates the selling price based on market conditions and entity-specific factors including features and functionality of the product and/or services, the geography of our customers, type of the Company’s markets. Any discounts or other reductions to the transaction price are allocated proportionately to all performance obligations within the multiple-element arrangement.

 

Contract Balances

 

Timing of revenue recognition may differ from the timing of invoicing to customers and receipt of payment. For the sale of its products, the Company generally recognizes revenue at a point in time through the ship-and-bill performance obligations. For service agreements, the Company generally invoices customers at the beginning of the coverage period and record revenue related to the billed amounts over time, equivalent to the coverage period of the maintenance and support contract.

 

Deferred revenue is comprised mainly of unearned revenue related to extended support and maintenance contracts (Ekso Care) but also includes other offerings for which the Company has been paid in advance and earn revenue when the Company transfers control of the product or service.

 

Deferred revenues consisted of the following:

 

		March 31,			December 31,
		2018			2017
Deferred extended maintenance and support		$	1,903		$	1,763
Deferred rental income			71			73
Customer deposits and advances			49			52
Deferred medical device revenues			35			31
Total deferred revenues			2,058			1,919
Less current portion			(1,292)			(1,103)
Deferred revenues, non-current		$	766		$	816

  

Deferred revenue activity consisted of the following:

 

		Three months ended
		March 31, 2018
Beginning balance		$	1,919
Deferral of revenue			703
Recognition of deferred revenue			(564)
Ending balance		$	2,058

 

At March 31, 2018, our deferred revenue, was $2,058 . Excluding customer deposits, we expect to recognize approximately $712 of the deferred revenue in the remainder of 2018, $543 in 2019, and $754 thereafter.

 

As of March 31, 2018, and December 31, 2017, accounts receivable, net of allowance for doubtful accounts, were $3,574 and $2,760, respectively, and are included in current assets on the Company’s consolidated balance sheets.

 

The allowance for doubtful accounts reflects the Company’s best estimate of probable losses inherent in the accounts receivable balance. The Company determines the allowance based on known troubled accounts, historical experience, and other currently available evidence. Payment terms and conditions vary by contract type, although terms generally include a requirement of payment within 30 to 60 days.

 

Disaggregation of revenue

 

The following table disaggregates our revenue by major source for the three months ended March 31, 2018 (in thousands):

 

		Device and Related
		Medical			Industrial			Total
Device revenue		$	1,663		$	386		$	2,049
Service, support and rentals			387			-			387
Parts and other			72			10			82
		$	2,122		$	396		$	2,518