Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 100,150	$ 136,604
Short-term investments	34,694	0
Accounts receivable	5,629	153
Prepaid expenses and other current assets	3,509	2,938
Total current assets	143,982	139,695
Investments at fair value	75,004	104,754
Investment - other	8,195	2,195
Patents, net	23,099	61,917
Other assets	187	207
Total assets	250,467	308,768
Current liabilities:
Accounts payable and accrued expenses	8,855	7,956
Royalties and contingent legal fees payable	4,765	1,601
Total current liabilities	13,620	9,557
Other liabilities	2,471	3,552
Total liabilities	16,091	13,109
Commitments and contingencies (Note 6)
Stockholders' equity:
Preferred stock, par value $0.001 per share; 10,000,000 shares authorized; no shares issued or outstanding	0	0
Common stock, par value $0.001 per share; 100,000,000 shares authorized; 49,495,064 and 50,639,926 shares issued and outstanding as of June 30, 2018 and December 31, 2017, respectively	49	51
Treasury stock, at cost, 2,919,828 and 1,729,408 shares as of June 30, 2018 and December 31, 2017, respectively	(39,272)	(34,640)
Additional paid-in capital	650,265	648,996
Accumulated comprehensive loss	(202)	(88)
Accumulated deficit	(377,977)	(320,018)
Total Acacia Research Corporation stockholders' equity	232,863	294,301
Noncontrolling interests in operating subsidiaries	1,513	1,358
Total stockholders' equity	234,376	295,659
Total liabilities and stockholders' equity	$ 250,467	$ 308,768