13. Revenue Recognition

CRA offers consulting services in two broad areas: litigation, regulatory, and financial consulting and management consulting. Together, these two service areas comprised 100.0% of CRA's consolidated revenues for the fiscal quarter ended April 1, 2017. CRA recognizes all project revenue on a gross basis based on consideration of the criteria set forth in ASC Topic 605-45, Principal Agent Considerations.

The contracts that CRA enters into and operates under specify whether the engagement will be billed on a time-and-materials or a fixed-price basis. Most of CRA's revenue is derived from time-and-materials service contracts. Revenues from time-and-materials service contracts are recognized as services are provided based upon hours worked and contractually agreed-upon hourly rates, as well as indirect fees based upon hours worked. Revenues from a majority of CRA's fixed-price engagements are recognized on a proportional performance method based on the ratio of costs incurred, substantially all of which are labor-related, to the total estimated project costs. In general, project costs are classified in costs of services and are based on the direct salary of the consultants on the engagement plus all direct expenses incurred to complete the engagement, including any amounts billed to CRA by its non-employee experts.

CRA's billed and unbilled receivables consist of receivables from a broad range of clients in a variety of industries located throughout the U.S. and in other countries. CRA performs a credit evaluation of its clients to minimize its collectability risk. Periodically, CRA will require advance payment from certain clients. However, CRA does not require collateral or other security. CRA maintains accounts receivable allowances for estimated losses and disputed amounts resulting from clients' failures to make required payments. CRA bases its estimates on historical collection experience, current trends, and credit policy. In determining these estimates, CRA examines historical write-offs of its receivables and reviews client accounts to identify any specific customer collection issues. If the financial condition of any of CRA's customers were to deteriorate, resulting in an impairment of their ability or intent to make payment, additional allowances may be required.

A rollforward of the accounts receivable allowance is as follows (in thousands):

	Fiscal Quarter Ended			Fiscal Year Ended
	April 1, 2017			December 31, 2016
Balance at beginning of period	$	4,253		$	3,648
Increases to reserve		1,688			2,761
Amounts written off		(659	)		(2,156	)
Effects of foreign currency translation		4			—

Balance at end of period	$	5,286		$	4,253

A rollforward of the unbilled receivables allowance is as follows (in thousands):

	Fiscal Quarter Ended			Fiscal Year Ended
	April 1, 2017			December 31, 2016
Balance at beginning of period	$	1,720		$	2,354
Increases to reserves		884			2,102
Amounts written off		(242	)		(2,736	)
Effects of foreign currency translation		—			—

Balance at end of period	$	2,362		$	1,720

Amounts deemed uncollectible are recorded as a reduction to revenues.

Revenues also include reimbursable expenses, which include travel and other out-of-pocket expenses, outside consultants, and other reimbursable expenses. Reimbursable expenses are as follows (in thousands):

	Fiscal Quarter Ended
	April 1, 2017		April 2, 2016
Reimbursable expenses	$	9,140	$	8,030

CRA collects goods and services and value added taxes from customers and records these amounts on a net basis, which is within the scope of ASC Topic 605-45, Principal Agent Considerations.