9. SUPPLEMENTAL CONSOLIDATED BALANCE SHEET INFORMATION

Accounts Receivable, net

The components of accounts receivable were as follows (shown in thousands):


	December 31,		December 31,
	2012		2011
Billed amounts	$	159,399	$	138,664
Engagements in process		54,685		55,350
Allowance for uncollectible accounts		(15,375)		(14,973)
Accounts receivable, net	$	198,709	$	179,041

Receivables attributable to engagements in process represent balances for services that have been performed and earned but have not been billed to the client. Services are generally billed on a monthly basis for the prior month’s services. Our allowance for doubtful accounts receivable is based on historical experience and management judgment and may change based on market conditions or specific client circumstances.

Prepaid expenses and other current assets

The components of prepaid expenses and other current assets were as follows (shown in thousands):


	December 31,		December 31,
	2012		2011
Notes receivable - current	$	7,701	$	7,579
Other prepaid expenses and other current assets		17,353		15,187
Prepaid expenses and other current assets	$	25,054	$	22,766

Other assets

The components of other assets were as follows (shown in thousands):


	December 31,		December 31,
	2012		2011
Notes receivable - non-current	$	13,916	$	10,707
Prepaid expenses and other non-current assets		16,501		15,246
Other assets	$	30,417	$	25,953

Notes receivable represent unsecured employee loans. These loans were issued to recruit and retain certain senior-level consultants. During the years ended December 31, 2012 and 2011, we issued unsecured employee loans aggregating $11.4 million and $6.0 million, respectively. The principal amount and accrued interest on these loans is either paid by the consultant or forgiven by us over the term of the loans so long as the consultant remains continuously employed by us and complies with certain contractual requirements. The expense associated with the forgiveness of the principal amount of the loans is recorded as compensation expense over the service period, which is consistent with the term of the loans.

Prepaid expenses and other assets include sign-on and retention bonuses that are generally recoverable from an employee if the employee terminates employment prior to fulfilling his or her obligations to us. These amounts are amortized as compensation expense over the period in which they are recoverable from the employee generally in periods up to seven years. During the years ended December 31, 2012 and 2011, we granted $11.0 million and $10.4 million, respectively, of sign-on and retention bonuses. At December 31, 2012, we had a balance of $19.2 million in unamortized sign-on and retention bonuses included in prepaid expenses and other current assets and non-current assets.

Property and Equipment, net

Property and equipment, net consisted of (shown in thousands):


	December 31,		December 31,
	2012		2011
Furniture, fixtures and equipment	$	63,497	$	60,935
Software		39,608		35,473
Leasehold improvements		40,052		39,410
Property and equipment, at cost		143,157		135,818
Less: accumulated depreciation and amortization		(97,815)		(94,680)
Property and equipment, net	$	45,342	$	41,138

During the year ended December 31, 2012, we invested in our technology infrastructure and entered into a new lease for office space in Washington, D.C. Additionally, we disposed of $11.0 million in fully depreciated assets. We also made a cash payment of $1.6 million towards liabilities relating to additions made in the prior year and we accrued $1.2 million in liabilities relating to additions made this year. We classified $1.6 million of equipment, at cost, as assets held for sale which had a net book value of $0.5 million and which we subsequently sold at no gain or loss.

Other Current Liabilities

The components of other current liabilities were as follows (shown in thousands):


	December 31,		December 31,
	2012		2011
Deferred acquisition liabilities	$	10,863	$	11,732
Deferred revenue		17,366		12,579
Deferred rent		2,995		2,028
Commitments on abandoned real estate (See Note 13)		748		1,222
Interest rate swap liability (See Note 10)		-		417
Other liabilities		3,782		4,644
Other current liabilities	$	35,754	$	32,622

The deferred acquisition liabilities at December 31, 2012 consisted of cash obligations related to definitive and contingent purchase price considerations recorded at net present value and fair value, respectively. During the year ended December 31, 2012, we made cash payments of $8.6 million in connection with deferred contingent acquisition liabilities relating to prior period acquisitions and $4.9 million in connection with definitive deferred acquisition liabilities. During the year ended December 31, 2012, we recorded $7.2 million in deferred acquisition liabilities, which included $6.4 million and $0.8 million of definitive and contingent purchase price obligations, respectively. In addition, during the year ended December 31, 2012, we made a net adjustment of $1.1 million relating to changes in the estimated fair value of performance-based contingent acquisition liabilities included in deferred acquisition liabilities above.

The current portion of deferred rent relates to rent allowances and incentives on lease arrangements for our office facilities that expire at various dates through 2022.

Deferred revenue represents advance billings to our clients for services that have not yet been performed and earned. Deferred revenue increased mainly due to a greater concentration of services that traditionally include advance billings.

Other Non-Current Liabilities

The components of other non-current liabilities were as follows (shown in thousands):


	December 31,		December 31,
	2012		2011
Deferred acquisition liabilities	$	14,783	$	4,326
Deferred rent - long term		11,034		9,429
Commitments on abandoned real estate (See Note 13)		487		453
Interest rate swap liability (See Note 11)		515		42
Other non-current liabilities		8,787		6,195
Total other non-current liabilities	$	35,606	$	20,445

The long-term portion of deferred rent is primarily rent allowances and incentives related to leasehold improvements on lease arrangements for our office facilities that expire at various dates through 2022. During the year ended December 31, 2012, we recorded $1.9 million in long and short-term deferred rent above for an adjustment relating to an above market lease acquired during 2012.