Balance Sheets Details

Accounts receivable

The following is a summary of activity in our allowance for doubtful accounts for the periods presented (in thousands):



	December 31,
	2017			2016			2015
Allowance - beginning of period	$	(421	)	$	(421	)	$	(428	)
Recoveries from bad debts	—			—			7
Write-offs and other ⁽¹⁾	387			—			—
Allowance - end of period	$	(34	)	$	(421	)	$	(421	)

⁽¹⁾ The change in allowance for doubtful accounts was mainly related to the write-off of receivables from a foreign customer.

Inventories

Inventories consisted of the following (in thousands):

⁽¹⁾ Raw materials include active pharmaceutical ingredients and other raw materials.

⁽²⁾ Work-in-process and finished goods include third party manufacturing costs and labor and indirect costs we incur in the production process.

Property and Equipment, net

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



	December 31,
	2017			2016
Laboratory equipment ⁽¹⁾	$	19,777		$	18,849
Leasehold improvements	10,327			10,395
Computer equipment and software	3,695			3,267
Office equipment and furniture	1,185			1,171
Construction in progress ⁽²⁾	85			124
Property and equipment	35,069			33,806
Less: accumulated depreciation and amortization	(32,254		)	(31,651		)
Property and equipment, net	$	2,815		$	2,155

⁽¹⁾ Fully depreciated laboratory equipment with a cost of $0.2 million and $2.3 million were retired during 2017 and 2016, respectively.

⁽²⁾ Construction in progress includes equipment received but not yet placed into service pending installation.

Goodwill

There were no changes in the carrying value of goodwill of $3.2 million during 2017 and 2016.

Other Accrued Liabilities

Other accrued liabilities consisted of the following (in thousands):



	December 31,
	2017		2016
Accrued purchases ⁽¹⁾	$	941	$	67
Accrued professional and outside service fees	2,393		746
Deferred rent	258		168
Lease incentive obligation	425		425
Other	345		705
Total	$	4,362	$	2,111

⁽¹⁾ Amount represents products and services received but have not been billed as of December 31, 2017 and 2016.