	December 31,
	2020		2019
Cash	$	88,046	$	40,715
Money market funds		590,347		85,551
Total cash and cash equivalents	$	678,393	$	126,266

The Company’s investments consist of available-for-sale debt investments, marketable equity investments, term deposit and certificate of deposit. The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s investments by major investments type are summarized in the tables below (in thousands):

	December 31, 2020
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
Bond and mutual funds	$	8,147	$	—	$	(3	)	$	8,144
Equity investments		125		119		—			244
Total investments	$	8,272	$	119	$	(3	)	$	8,388

	December 31, 2019
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
U.S. treasury notes and bills	$	426,995	$	536	$	(25	)	$	427,506
Certificates of deposit		30,000		32		—			30,032
Bond and mutual funds		10,730		86		—			10,816
Equity investments		125		130		—			255
Total investments	$	467,850	$	784	$	(25	)	$	468,609

The contractual maturities of the available-for-sale investments were as follows (in thousands):

The Company periodically reviews its available-for-sale investments and term deposit for other-than-temporary impairment. The Company considers factors such as the duration, severity and the reason for the decline in value, the potential recovery period and its intent to sell. For debt securities, the Company also considers whether (i) it is more likely than not that the Company will be required to sell the debt securities before recovery of their amortized cost basis, and (ii) the amortized cost basis cannot be recovered as a result of credit losses. During the three years ended December 31, 2020, the Company did not recognize any other-than-temporary impairment loss.

	December 31,
	2020		2019
Raw materials	$	2,303	$	325
Work-in-progress		8,114		2,264
Finished goods		6,113		4,298
Total inventories	$	16,530	$	6,887

The Company started capitalizing inventory costs in June 2019 when FibroGen Beijing began productions of roxadustat for commercial sales purposes. The Company started capitalizing pre-launch inventory costs in the U.S. the second quarter of 2020 prior to regulatory approval. As of December 31, 2020, pre-launch inventory capitalized was 29% of the total inventory balance. The provision to write-down excess and obsolete inventory was nominal for the years ended December 31, 2020 and 2019.

Prepaid expenses and other current assets consisted of the following (in thousands):

	December 31,
	2020			2019
Unbilled contract assets	$	2,147		$	180,000
Deferred revenues from associated contracts		(2,147	)		(54,790	)
Net unbilled contract assets		—			125,210
Prepaid assets		8,353			6,464
Other current assets		1,807			1,717
Total prepaid expenses and other current assets	$	10,160		$	133,391

The unbilled contract assets as of December 31, 2020 were related to unbilled co-development revenue under the China Amendment with AstraZeneca. The unbilled contract assets as of December 31, 2019 were related to two regulatory milestones totaling $130.0 million under the Europe Agreement with Astellas associated with the planned MAA submission in Europe, and a $50.0 million regulatory milestone under the U.S./RoW Agreement with AstraZeneca associated with the NDA submission in the U.S., which was submitted in December 2019 and accepted for review in February 2020. See Note 4, Collaboration Agreements and Revenues, for details.

	December 31,
	2020			2019
Leasehold improvements	$	102,006		$	101,548
Laboratory equipment		18,143			17,329
Machinery		8,312			8,217
Computer equipment		9,545			8,399
Furniture and fixtures		6,128			5,822
Construction in progress		760			1,792
Total property and equipment	$	144,894		$	143,107
Less: accumulated depreciation		(111,247	)		(100,364	)
Property and equipment, net	$	33,647		$	42,743

Depreciation expense for the years ended December 31, 2020, 2019 and 2018 was $11.7 million, $11.1 million, and $6.6 million, respectively.

Accrued and other current liabilities consisted of the following (in thousands):

	December 31,
	2020		2019
Preclinical and clinical trial accruals	$	44,113	$	16,279
API product price adjustment		—		36,324
Payroll and related accruals		22,800		19,784
Contract liabilities to pharmaceutical distributors		15,137		—
Accrued co-promotion expenses - current		11,537		—
Roxadustat profit share to AstraZeneca		7,007		—
Property taxes and other		5,970		2,044
Professional services		4,869		4,842
Other		8,088		4,543
Total accrued and other current liabilities	$	119,521	$	83,816

The API product price adjustment of $36.3 million accrued as of December 31, 2019 was related to the change in estimated variable consideration of API product at the time the roxadustat listed price was issued by the Japanese Ministry of Health, Labour and Welfare in the fourth quarter of 2019. This amount was fully paid during the first quarter of 2020. Refer to Note 4, Collaboration Agreements and Revenues, for details.

On July 8, 2020, the Parties entered into an amendment to the China Agreement, relating to the development and commercialization of roxadustat in China, which revised, among other things, the arrangements and calculation of the estimated co-promotion expenses payable to AstraZeneca for its sales and marketing efforts associated with the commercial sales for roxadustat in China. As a result, the previously accrued long-term co-promotion expenses were significantly reduced during the third quarter of 2020. $11.5 million of the recalculated accrued co-promotion expenses is anticipated to be paid within the next 12 months, therefore was recorded as a current liability as of December 31, 2020.

The profit share liability of $7.0 million to AstraZeneca as of December 31, 2020 represented the profit/loss share between FibroGen Beijing and AstraZeneca that is calculated pursuant to the China Agreement. This liability correspondingly reduced the deferred revenue related to the performance obligation in accordance with the China Agreement. Refer to Note 4, Collaboration Agreements and Revenues, for details.

	December 31,
	2020		2019
Accrued long-term co-promotion expenses	$	27,424	$	53,071
Other long-term tax liabilities		8,675		8,913
Operating lease liabilities, non-current		853		942
Other		2,690		2,481
Total other long-term liabilities	$	39,642	$	65,407

The accrued long-term co-promotional expenses of $53.1 million as of December 31, 2019 was related to the estimated amount payable to AstraZeneca for its sales and marketing efforts related to the commercial launch for roxadustat in China. As mentioned above, the China Amendment revised the arrangements and calculation of the estimated co-promotion expenses payable to AstraZeneca. As a result, we reversed approximately $84.4 million of previously accrued long-term co-promotion expenses during the third quarter of 2020. $27.4 million of the recalculated accrued co-promotion expenses remained in the long-term liabilities as of December 31, 2020, as it is not anticipated to be paid within the next 12 months.