CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
OPERATING ACTIVITIES:
Net loss	$ (15,002)	$ (20,774)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	531	415
Amortization of right-of-use operating lease asset	544
Share-based compensation expense	1,185	753
Non-cash interest expense	105
Gain (loss) from equity-method investment	15	(47)
Changes in operating assets and liabilities
Accounts receivable	1,856	(643)
Prepaid expense and other assets	(1,973)	611
Accounts payable	1,489	938
Accrued liabilities	1,432	9
Deferred revenue	10,941	3,647
Net cash provided by (used in) operating activities	1,093	(14,997)
INVESTING ACTIVITIES:
Proceeds from maturities of short-term investments		30,211
Purchases of short-term investments		(9,093)
Acquisition of property and equipment	(503)	(1,253)
Net cash (used in) provided by investing activities	(503)	19,865
FINANCING ACTIVITIES:
Proceeds from the issuance of restricted common stock and option, net of issuance costs	15,545
Proceeds from the issuance of common stock, net of issuance costs	21,278
Proceeds from exercise of stock options	50	332
Net cash provided by financing activities	36,873	332
NET INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	37,463	5,200
Cash, cash equivalents and restricted cash at beginning of the period	36,816	25,238
Cash, cash equivalents and restricted cash at end of the period	74,279	30,438
Supplemental disclosure of cash flow information
Cash paid for interest	508
Non-cash investing activities
Right-of-use asset obtained in exchange for lease liabilities	5,868
Sale of intangible assets for equity investment		590
Release of repurchase liability for restricted shares		37
Purchase of property and equipment in accounts payable	$ 126	$ 177