CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows used in operating activities:
Net loss	$ (12,865,000)	$ (2,695,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization of property and equipment	232,000	224,000
Amortization of intangibles	0	3,000
Stock-based compensation	1,557,000	2,334,000
Deferred income taxes	0	(1,629,000)
Changes in operating assets and liabilities:
Accounts and other receivables	(527,000)	(3,561,000)
Prepaid income taxes	0	725,000
Prepaid expenses and other current assets	150,000	111,000
Intangibles and other assets	(55,000)	(16,000)
Accounts payable	1,000,000	2,328,000
Accrued compensation and other current liabilities	(1,741,000)	(2,270,000)
Deferred revenue	(2,046,000)	(1,148,000)
Other long-term liabilities	(22,000)	(262,000)
Net cash used in operating activities	(14,317,000)	(5,856,000)
Cash flows used in investing activities:
Purchases of short-term investments	(9,931,000)	(9,945,000)
Proceeds from maturities of short-term investments	10,000,000	10,000,000
Purchases of property and equipment	(83,000)	(65,000)
Net cash used in investing activities	(14,000)	(10,000)
Cash flows provided by financing activities:
Issuance of common stock under employee stock purchase plan	175,000	128,000
Exercise of stock options	401,000	1,604,000
Net cash provided by financing activities	576,000	1,732,000
Net decrease in cash and cash equivalents	(13,755,000)	(4,134,000)
Cash and cash equivalents:
Beginning of period	56,865,000	25,013,000
End of period	43,110,000	20,879,000
Supplemental disclosure of cash flow information
Cash paid (received) for taxes	39,000	(529,000)
Supplemental disclosure of noncash operating, investing, and financing activities
Amounts accrued for property and equipment	11,000	0
Release of Restricted Stock Units and Awards under company stock plan	$ 1,768,000	$ 1,777,000