Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 49,319	$ 83,343
Short-term investments	29,870	3,963
Accounts receivable, net	31,071	32,386
Prepaid expenses and other	9,975	9,578
Inventory	995	1,708
Total current assets	121,230	130,978
Non-current assets:
Property and equipment, net	9,603	10,354
Operating lease right-of-use assets	16,345	0
Goodwill	133,031	133,031
Intangible assets, net	3,542	5,417
Deferred income tax assets	46,961	46,484
Other non-current assets	1,319	1,448
Total non-current assets	210,801	196,734
Total assets	332,031	327,712
Current liabilities:
Accounts payable	3,605	2,010
Accrued compensation and benefits	11,465	11,348
Accrued taxes	1,605	1,822
Deferred revenue	27,668	26,106
Operating lease liabilities	5,303	0
Other current liabilities	2,531	3,662
Total current liabilities	52,177	44,948
Non-current liabilities:
Asset retirement obligations	6,756	6,513
Operating lease liabilities	11,658	0
Other non-current liabilities	643	1,697
Total non-current liabilities	19,057	8,210
Total liabilities	71,234	53,158
Commitments and contingencies (Note 12)
Stockholders' equity:
Preferred stock	0	0
Common stock	2	2
Additional paid-in capital	85,614	90,559
Accumulated other comprehensive loss	(1,499)	(1,301)
Retained earnings	176,680	185,294
Total stockholders’ equity	260,797	274,554
Total liabilities and stockholders' equity	$ 332,031	$ 327,712