Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 40,020	$ 12,024
Short-term investments	87,271	105,740
Accounts receivable	51,090	30,205
Prepaid expenses and other current assets	1,449	722
Total current assets	179,830	148,691
Property and equipment, net	1,210	905
Long-term investments	7,929	5,997
Other assets	359	279
Total assets	189,328	155,872
Current liabilities:
Accounts payable	1,400	671
Accrued liabilities	8,575	8,645
Deferred revenue	22,962	29,019
Total current liabilities	32,937	38,335
Long-term debt, net	4,676
Noncurrent deferred revenue	72,197	67,547
Other non-current liabilities	251	101
Total liabilities	110,061	105,983
Commitments (Note 8)
Stockholders' equity:
Preferred stock, $0.001 par value, 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.001 par value, 200,000,000 shares authorized; 48,837,060 shares and 48,057,920 shares issued and outstanding at December 31, 2017 and December 31, 2016, respectively	49	48
Additional paid-in capital	368,553	356,966
Note receivable	(16)	(16)
Accumulated other comprehensive loss	(119)	(50)
Accumulated deficit	(289,200)	(307,059)
Total stockholders' equity	79,267	49,889
Total liabilities and stockholders' equity	$ 189,328	$ 155,872