CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (16,746)	$ (5,200)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	283	166
Premium amortization and discount accretion on marketable securities	139	(516)
Equity‑based compensation	2,544	499
Change in operating assets and liabilities:
Accounts receivable	(218)	(378)
Prepaid expenses and other current assets	279	(58)
Other assets	33	9
Accounts payable	(307)	1,142
Accrued expenses	(1,024)	224
Deferred revenue	(3,905)	4,309
Deferred rent	(21)	(9)
Net cash (used in) provided by operating activities	(18,943)	188
Cash flows from investing activities:
Purchases of marketable securities	(9,089)	(143,111)
Proceeds from maturities of marketable securities	33,000
Purchase of property and equipment	(295)	(559)
Net cash provided by (used in) investing activities	23,616	(143,670)
Cash flows from financing activities:
Proceeds from issuance of Common Stock pursuant to stock options exercise	122
Proceeds from issuance of Common Stock under Employee Stock Purchase Plan	681
Net cash provided by financing activities	803
Net (decrease) increase in cash and cash equivalents and restricted cash	5,476	(143,482)
Cash and cash equivalents and restricted cash, beginning of period	101,834	186,176
Cash and cash equivalents and restricted cash, end of period	107,310	$ 42,694
Non-cash investing and financing activities:
Purchases of property and equipment in accounts payable and accrued expenses	30
Amounts from exercise of stock options included in prepaid expenses and other current assets	45
Supplemental cash flow information:
Cash paid for taxes	$ 480