Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 57,359	$ 128,809
Trading securities - debt	93,843	33,642
Trading securities - equity	17,140	3,012
Accounts receivable	511	32,884
Prepaid expenses and other current assets	2,912	3,125
Total current assets	171,765	201,472
Long-term restricted cash	35,000	0
Investment at fair value (Note 6)	1,500	7,459
Other investments (Note 6)	0	8,195
Patents, net of accumulated amortization	7,814	6,587
Leased right-of-use assets	1,264	0
Other non-current assets	818	236
Total assets	218,161	223,949
Current liabilities:
Accounts payable	1,765	3,698
Accrued expenses and other current liabilities	7,265	4,299
Accrued compensation	507	350
Royalties and contingent legal fees payable	2,178	22,688
Total current liabilities	11,715	31,035
Series A warrant liabilities	3,568
Series A embedded derivative liabilities	17,974	0
Long-term lease liabilities	1,264	0
Other long-term liabilities	593	1,674
Total liabilities	35,114	32,709
Commitments and contingencies (Note 10)
Series A redeemable convertible preferred stock, par value $0.001 per share; stated value $100 per share; 350,000 shares authorized, issued and outstanding as of December 31, 2019; no shares authorized, issued or outstanding as of December 31, 2018; aggregate liquidation preference of $35,125 and $0 as of December 31, 2019 and December 31, 2018, respectively (Note 16)	8,089	0
Stockholders' equity:
Preferred stock, par value $0.001 per share; 10,000,000 shares authorized;	0	0
Common stock, par value $0.001 per share; 100,000,000 shares authorized; 50,370,987 and 49,639,319 shares issued and outstanding as of December 31, 2019 and December 31, 2018, respectively	50	50
Treasury stock, at cost, 2,919,828 shares as of September 30, 2019 and December 31, 2018	(39,272)	(39,272)
Additional paid-in capital	652,003	651,156
Accumulated deficit	(439,656)	(422,541)
Total Acacia Research Corporation stockholders' equity	173,125	189,393
Noncontrolling interests	1,833	1,847
Total stockholders' equity	174,958	191,240
Total liabilities, redeemable convertible preferred stock, and stockholders' equity	$ 218,161	$ 223,949