CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 87,201	$ 30,315
Short-term investments	51,993	114,981
Accounts receivable, net of allowance for doubtful accounts of $954 and $963 in 2021 and 2020, respectively	30,128	34,140
Prepaid expenses and other current assets	12,715	13,944
Total current assets	182,037	193,380
Property and equipment, net	37,977	39,242
Operating lease right-of-use assets, net	5,928	6,672
Goodwill	15,305	15,774
Intangible assets, net	22,875	24,573
Deferred tax assets, net	176	249
Other non-current assets	9,372	7,690
Total assets	273,670	287,580
Current liabilities:
Accounts payable	7,078	4,399
Accrued compensation and related benefits	7,278	8,339
Accrued and other current liabilities	5,913	6,309
Operating lease liabilities - current portion	1,770	1,926
Deferred revenues - current portion	15,946	19,895
Billings in excess of recognized revenues	2,185	1,337
Total current liabilities	40,170	42,205
Long-term income taxes payable	2,718	2,956
Non-current operating lease liabilities	5,832	6,516
Other non-current liabilities	1,826	1,397
Total liabilities	50,546	53,074
Commitments and contingencies (Note 13)
Stockholders' equity:
Preferred stock, $0.00015 par value, 5,000 shares authorized, no shares issued and outstanding
Common stock, $0.00015 par value, 70,000 shares authorized; shares issued 47,011 and 46,400, respectively; shares outstanding 37,086 and 36,850, respectively	6	6
Additional paid-in-capital	415,063	407,173
Treasury stock at cost, 9,925 and 9,550 shares, respectively	(103,088)	(96,215)
Accumulated deficit	(88,314)	(76,233)
Accumulated other comprehensive loss	(543)	(225)
Total stockholders' equity	223,124	234,506
Total liabilities and stockholders' equity	$ 273,670	$ 287,580