CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows provided by (used in) operating activities:
Net income (loss)	$ (2,685)	$ (21,023)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	1,681	1,265
Stock-based compensation	3,433	4,371
Other	(95)	467
Changes in operating assets and liabilities:
Accounts and other receivables	2,019	(814)
Prepaid expenses and other current assets	4,147	(2,239)
Increase (Decrease) in Deposit Assets	(4,889)	(6,533)
Other assets	1,471	(3,993)
Accounts payable	(642)	(1,440)
Accrued compensation	(2,013)	(1,567)
Other current liabilities	(1,465)	(15)
Deferred revenue	(2,984)	(3,312)
Other long-term liabilities	(966)	3,967
Net cash used in operating activities	(2,988)	(30,866)
Cash flows provided by (used in) investing activities:
Purchases of short-term investments	0	(8,930)
Proceeds from maturities of short-term investments	3,000	14,000
Purchases of property and equipment	(40)	(12)
Net cash provided by investing activities	2,960	5,058
Cash flows provided by (used in) financing activities:
Cash paid for purchases of treasury shares	(30,642)	0
Proceeds from issuance of common stock under employee stock purchase plan	134	165
Proceeds from stock options exercises	19	1,240
Net cash provided by (used in) financing activities	(30,489)	1,405
Net decrease in cash and cash equivalents	(30,517)	(24,403)
Cash and cash equivalents:
Beginning of period	86,478	110,988
End of period	55,961	86,585
Supplemental disclosure of cash flow information:
Cash paid for income taxes	65	104
Supplemental disclosure of non-cash operating, investing, and financing activities:
Release of restricted stock units and awards under company stock plan	2,801	7,148
Leased assets obtained in exchange for new operating lease liabilities	$ 577	$ 0